Hybrid energy off highway vehicle electric power storage system and method

ABSTRACT

A computerized system for use in connection with a hybrid energy off highway vehicle system of a off highway vehicle. The hybrid energy off highway vehicle system includes an off highway vehicle, a primary power source, and an off highway vehicle traction motor propelling the off highway vehicle in response to the primary electric power, and an energy capture system for storing and/or transferring electrical power. An energy management processor carried on the off highway vehicle controls transmission of electrical power among the primary electric power generator, the vehicle propulsion system, an electrical energy capture system, and each of the plurality of dynamic braking resistance grid circuits during motoring, operating and braking the travel of the off highway vehicle.

CROSS REFERENCE TO RELATED APPLICATIONS

The invention of the present application is a Continuation-in-Part thatclaims benefit of U.S. patent application Ser. No. 10/378,335 (U.S. Pat.No. 6,973,880), filed on Mar. 3, 2003, and entitled “HYBRID ENERGY OFFHIGHWAY VEHICLE ELECTRIC POWER STORAGE SYSTEM AND METHOD”, which CIPfrom U.S. patent application Ser. No. 10/033,347 (U.S. Pat. No.6,591,758), filed on Dec. 26, 2001, and entitled “HYBRID ENERGYLOCOMOTIVE POWER STORAGE SYSTEM”, and from U.S. Provisional ApplicationSer. No. 60/278,975, filed on Mar. 27, 2001, the entire disclosure ofwhich is incorporated herein by reference.

The following commonly owned, applications are related to the presentapplication and are incorporated herein by reference: U.S. patentapplication Ser. No. 10/378,431 (Publication No. 20030151387), filed onMar. 3, 2003, and entitled “HYBRID ENERGY; OFF HIGHWAY VEHICLE POWERMANAGEMENT SYSTEM AND METHOD”; U.S. patent application Ser. No.10/033,172(U.S. Pat. No. 6,615,118), filed on Dec. 26, 2001, andentitled “HYBRID ENERGY POWER MANAGEMENT SYSTEM AND METHOD”, allowedDec. 23, 2002; U.S. patent application Ser. No. 10/033,191 (U.S. Pat.No. 6,612,246), filed on Dec. 26, 2001, and entitled “HYBRID ENERGYLOCOMOTIVE SYSTEM AND METHOD”; and U.S. patent application Ser. No.10/032,714 (U.S. Pat. No. 6,612,245), filed on Dec. 26, 2001, andentitled “LOCOMOTIVE ENERGY TENDER”.

FIELD OF THE INVENTION

The invention relates generally to energy management systems and methodsfor use in connection with a large, Off-Highway Vehicle such as arailway locomotive, mining truck or excavator. In particular, theinvention relates to a system and method for managing the storage andtransfer of electrical energy, such as dynamic braking energy or excessprime mover power, produced by Off-Highway Vehicles driven by electrictraction motors.

BACKGROUND OF THE INVENTION

FIG. 1A is a block diagram of an exemplary prior art Off HighwayVehicle. In particular, FIG. 1A generally reflects a typical prior, artdiesel-electric Off Highway Vehicle. Off Highway Vehicles includelocomotives, and mining trucks and excavators, where mining trucks andexcavators range from 100-ton capacity to 400-ton capacity, but may besmaller or larger. Off Highway Vehicles typically have a power weightratio of less than 10 h.p. per ton with a ratio of 5 h p. per ton beingcommon. Off Highway Vehicles typically also utilize dynamic or electricbraking. This is in contrast to a vehicle such as a passenger bus thathas a ratio of 15 h.p. per ton or more and utilizes mechanical orresistive braking.

As illustrated in FIG. 1A, the Off Highway Vehicle 100 includes a dieselprimary power source 102 driving an alternator/rectifier 104. As isgenerally understood in the art, the alternator/rectifier 104 providesDC electric power to an inverter 106 that converts the AC electric powerto a form suitable for use by a traction motor 108. One common OffHighway Vehicle configuration includes one inverter/traction motor perwheel 109, with two wheels 109 comprising the equivalent of an axle (notshown). Such a configuration results in one or two inverters per OffHighway Vehicle. FIG. 1A illustrates a single inverter 106 and a singletraction motor 108 for convenience. By way of example, large excavationdump trucks may employ motorized wheels such as the GEB23™ AC motorizedwheel employing the GE150AC™ drive system (both of which are availablefrom the assignee of the present system).

Strictly speaking, an inverter converts DC power to AC power. Arectifier converts AC power to DC power. The term “converter” is alsosometimes used to refer to inverters and rectifiers. The electricalpower supplied in this manner may be referred to as prime mover power(or primary electric power) and the alternator/rectifier 104 may bereferred to as a source of prime mover power. In a typical ACdiesel-electric Off Highway Vehicle application, the AC electric powerfrom the alternator is first rectified (converted to DC). The rectifiedAC is thereafter inverted (e.g., using power electronics such asInsulated Gate Bipolar Transistors (IGBTs) or thyristors operating aspulse width modulators) to provide a suitable form of AC power for therespective traction motor 108.

As is understood in the art, traction motors 108 provide the tractivepower to move Off Highway Vehicle 100 and any other vehicles, such asload vehicles, attached to Off Highway Vehicle 100. Such traction motors108 may be an AC or DC electric motors. When using DC traction motors,the output of the alternator is typically-rectified to provideappropriate DC power. When using AC traction motors, the alternatoroutput is typically rectified to DC and thereafter inverted tothree-phase AC before being supplied to traction motors 108.

The traction motors 108 also provide a braking force for controllingspeed or for slowing Off Highway Vehicle 100. This is commonly referredto as dynamic braking, and is generally understood in the art. Simplystated, when a traction motor 108 is not needed to provide motivatingforce, it can be reconfigured (via power switching devices) so that themotor operates as an electric power generator. So configured, thetraction motor 108 generates electric energy which has the effect ofslowing the Off Highway Vehicle. In prior art Off Highway Vehicles, suchas illustrated in FIG. 1A, the energy generated in the dynamic brakingmode is typically transferred to resistance grids 110 mounted on thevehicle housing. Thus, the dynamic braking energy is converted to heatand dissipated from the system. Such electric energy generated in thedynamic braking mode is typically wasted.

It should be noted that, in a typical prior art DC hybrid vehicle, thedynamic braking grids 110 are connected to the traction motors 108. In atypical prior art AC hybrid vehicle; however, the dynamic braking gridsare connected to the DC traction bus 122 because each traction motor 108is normally connected to the bus by way of an associated inverter 106(see FIG. 1B). FIG. 1A generally illustrates an AC hybrid vehicle with aplurality of traction motors; a single inverter is depicted forconvenience.

FIG. 1B is an electrical schematic of a typical prior art Off HighwayVehicle 100. It is generally known in the art to employ a singleelectrical energy source 102, however, two or more electrical energysources may be employed. In the case of a single electrical energysource, a diesel engine 102 coupled to an alternator 104 provides theprimary source power 104. In the case where two or more electricalenergy sources 102 are provided, a first system comprises the primemover power system that provides power to the traction motors 108. Asecond system (not shown) provides power for so-called auxiliaryelectrical systems (or simply auxiliaries). Such an auxiliary system maybe derived as an output of the alternator, from the DC output, or from aseparate alternator driven by the primary power source. For example, inFIG. 1B, a diesel engine 102 drives the prime mover power source 104(e.g., an alternator and rectifier), as well as any auxiliaryalternators (not illustrated) used to power various auxiliary electricalsubsystems such as, for example, lighting, air conditioning/heating,blower drives, radiator fan drives, control battery chargers, fieldexciters, power steering, pumps, and the like. The auxiliary powersystem may also receive power from a separate axle driven generator.Auxiliary power may also be derived from the traction alternator ofprime mover power source 104.

The output of prime mover power source 104 is connected toga DC bus 122that supplies DC power to the traction motor subsystems 124A-124B. TheDC bus 122 may also be referred to as a traction bus 122 because itcarries the power used by the traction motor subsystems. As explainedabove, a typical prior art diesel-electric Off Highway Vehicle includestwo traction motors 108, one per each wheel 109, wherein the two wheels109 operate as an axle assembly, or axle-equivalent. However, a systemmay be also be configured to include a single traction motor per axle orconfigured to include four traction motors, one per each wheel 109 of atwo axle-equivalent four-wheel vehicle. In FIG. 1B, each traction motorsubsystem 124A and 124B comprises an inverter (e.g., inverter 106A and106B) and a corresponding traction motor (e.g., traction motor 108A and108B, respectively).

During braking, the power generated by the traction motors 108& isdissipated through a dynamic braking grid subsystem 110. As illustratedin FIG. 1B, a typical prior art dynamic braking grid subsystem 110includes a plurality of contactors (e.g., DB1-DB5) for switching aplurality of power resistive elements between the positive and negativerails of the DC bus 122. Each vertical grouping of resistors may bereferred to as a string. One or more power grid cooling blowers (e.g.,BL1 and BL2) are normally used to remove heat generated in a string dueto dynamic braking. It is also understood that these contactors(DB1-DB5) can be replaced by solid-state switches like GTO/IGBTs and canbe modulated (like a chopper) to control the effective dynamic brakeresistance.

As indicated above, prior art Off Highway Vehicles typically waste theenergy generated from dynamic braking. Attempts to make productive useof such energy have been unsatisfactory. For example, one systemattempts to use energy generated by a traction motor 108 in connectionwith an electrolysis cell to generate hydrogen gas as a supplementalfuel source. Among the disadvantages of such a system are the safestorage of the hydrogen gas and the need to carry water for theelectrolysis process. Still other prior art systems fail to recapturethe dynamic braking energy at all, but rather selectively engage aspecial generator that operates when the associated vehicle travelsdownhill. One of the reasons such a system is unsatisfactory is becauseit fails to recapture existing braking energy and fails to make thecaptured energy available for reuse on board the Off Highway Vehicle.

Therefore, there is a need for an energy management system and methodthat control when energy is captured and stored, and when such energy isregenerated for later use.

SUMMARY OF THE INVENTION

In one aspect, the invention relates to a hybrid energy off highwayvehicle power storage system and method. The off highway vehicle systemincludes an off highway vehicle having a plurality of vehicle wheels. Anoff highway vehicle traction motor is associated with one of theplurality of vehicle wheels and has a rotatable shaft mechanicallycoupled to the one of the plurality of vehicle wheels. A primary powersource is carried on the off highway vehicle. The off highway vehiclehas an energy management processor. An electric power generator iscarried on the off highway vehicle and is responsive to said processor.The generator is connected to and driven by the primary power source forgenerating and selectively supplying primary electric power to the offhighway vehicle traction motor. The off highway vehicle traction motoris operable in response to the primary electric power to rotate therotatable shaft and to drive the one of the plurality of vehicle wheels.The off highway vehicle traction motor has a dynamic braking mode ofoperation wherein the off highway vehicle traction motor generateselectrical energy in the form of electricity. An electrical energycapture system is carried on the off highway vehicle. The capture systemis responsive to said processor and in electrical communication with theoff highway vehicle traction motor for selectively storing electricalenergy generated in the dynamic braking mode and selectively providingsecondary electric power from said stored electrical energy to thetraction motor to selectively supplement the primary electric power withthe secondary electric power so that said off highway vehicle tractionmotor is operable in response to the primary off highway vehicle powerand the secondary electric power. The processor provides a first controlsignal to the capture system to control the selective storing ofelectrical energy generated in the dynamic braking mode and to controlthe selective providing of secondary electric power to the off highwayvehicle traction motor to supplement the primary electric power. Theprocessor also provides a second control signal to the generator forcontrolling the selective supplying of primary electric power to the offhighway vehicle traction motor.

In another aspect, the invention relates to a hybrid energy off highwayvehicle system for use in connection with a off highway vehicle forpropelling the off highway vehicle. The system includes a primary powersource carried on the off highway vehicle and an energy managementprocessor. A power converter is driven by the primary power source andselectively provides primary electric power. The power converter isresponsive to the energy management processor. A traction bus is coupledto the power converter and carries the primary electric power. An offhighway vehicle traction system is coupled to the traction bus. Thetraction system has a motoring mode and a dynamic braking mode. Thetraction system propels the off highway vehicle in response to theprimary electric power in the motoring mode and generates electricalenergy in the dynamic braking mode. An electrical energy storage systemis carried on the off highway vehicle and is responsive to theprocessor. The electrical energy storage system is coupled to thetraction bus and selectively captures electrical energy generated by theoff highway vehicle traction system in the dynamic braking mode. Thestorage system selectively transfers the captured electrical energy assecondary electric power to the off highway vehicle traction system toaugment the primary electric power in the motoring mode. The off highwayvehicle traction system propels the off highway vehicle in response tothe secondary electric power. The processor provides a first controlsignal to the electrical energy storage system to control the selectivestoring of electrical energy, generated in the dynamic braking mode andto control the selective providing of secondary electric power to theoff highway vehicle traction motor to supplement the primary electricpower, and provides a second control signal to the power converter forcontrolling the selective supplying of primary electric power to the offhighway vehicle traction motor.

In yet another aspect, the invention relates to an electrical energycapture system for use in connection with a hybrid energy off highwayvehicle system of an off highway vehicle. The hybrid energy off highwayvehicle system includes an off highway vehicle, a primary power source,an vehicle electric generator connected to and driven by the primarypower source for selectively supplying primary electric power, and anoff highway vehicle traction motor propelling the off highway vehicle inresponse to the primary electric power. The off highway vehicle tractionmotor has a dynamic braking mode of operation generating electricalenergy. The electrical energy capture system includes an energymanagement processor carried on the off highway vehicle. An electricalenergy storage device is carried on the off-highway vehicle and is inelectrical communication with the off highway vehicle traction motor.The storage device is responsive to the processor, selectively storeselectrical energy generated in the dynamic braking mode, and selectivelyprovides secondary electric power from said stored electricityelectrical energy to the off highway, vehicle traction motor. The offhighway vehicle traction motor is responsive to the secondary electricpower. The processor provides a first control signal to the electricalenergy storage device to control the selective storing of the electricalenergy generated in the dynamic braking mode, and to control theselective providing of secondary electric power to the off highwayvehicle traction motor.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a block diagram of a prior art Off Highway Vehicle.

FIG. 1B is an electrical schematic of a prior art AC diesel-electric OffHighway Vehicle.

FIG. 2 is a block diagram of one embodiment of hybrid energy Off HighwayVehicle system.

FIG. 3 is a block diagram of one embodiment of hybrid energy Off HighwayVehicle system configured with a fuel cell and a load vehicle.

FIG. 4 is a block diagram illustrating one embodiment of an energystorage and generation system suitable for use in connection with hybridenergy Off Highway Vehicle system.

FIG. 5 is a block diagram illustrating an energy storage and generationsystem suitable for use in a hybrid energy Off Highway Vehicle system,including an energy management system for controlling the storage andregeneration of energy.

FIGS. 6A-6D are timing diagrams that illustrate one embodiment of anenergy management system for controlling the storage and regeneration ofenergy, including dynamic braking energy.

FIGS. 7A-7D are timing diagrams that illustrate another embodimentenergy management system for controlling the storage and regeneration ofenergy, including dynamic braking energy.

FIGS. 8A-8E are timing diagrams that illustrate another embodimentenergy management system for controlling the storage and regeneration ofenergy, including dynamic braking energy.

FIGS. 9A-9G are electrical schematics illustrating; several embodimentsof an electrical system suitable for use in connection with a hybridenergy vehicle.

FIGS. 10A-10C are electrical schematics illustrating additionalembodiments of an electrical system suitable for use in connection witha hybrid energy vehicle.

FIG. 11 is an electrical schematic that illustrates one embodiment ofconnecting electrical storage elements.

FIG. 12 is a flow chart that illustrates one method of operating ahybrid energy Off Highway Vehicle system.

FIG. 13 is a block diagram illustrating an energy management processorhaving computer executable instructions for controlling the transmissionof power during motoring, operating, and braking the travel of an offhighway vehicle.

Corresponding reference characters and designations generally indicatecorresponding parts throughout the drawings.

DETAILED DESCRIPTION OF ASPECTS OF THE INVENTION

FIG. 2 is a block diagram of one embodiment of a hybrid energy OffHighway Vehicle system 200. In this embodiment, the hybrid energy OffHighway Vehicle system preferably captures and regenerates at least aportion of the dynamic braking electric energy generated when thevehicle traction motors operate in a dynamic braking mode.

The Off Highway Vehicle system includes an Off Highway Vehicle 200having a primary energy source 104. In some embodiments, a powerconverter is driven by the primary energy source 102 and providesprimary electric power. A traction bus 122 is coupled to the powerconverter and carries the primary electric power. A traction drive 108is coupled to the traction bus 122. The traction drive 108 has amotoring mode in which the traction drive is responsive to the primaryelectric power for propelling the Off Highway Vehicle 200. The tractiondrive 108 has a dynamic braking mode of operation wherein the tractiondrive generates dynamic braking electrical energy. An energy managementsystem 206 comprises an energy management processor (not shown). Theenergy management system 206 determines a power storage parameter and apower transfer parameter. An energy capture and storage system 204 isresponsive to the energy management system 206. The energy capture andstorage system 204 selectively stores electrical energy as a function ofthe power storage parameter. The energy capture and storage system 204selectively supplies secondary electric power from the electrical energystored therein as a function of the power transfer parameter.

In one embodiment, the energy capture and storage system 204 selectivelyreceives electrical power generated during the dynamic braking mode ofoperation and stores it for later regeneration and use. In thealternative or in addition to receiving and storing dynamic brakingpower, energy capture and storage system 204 can also be constructed andarranged to receive and store power from other sources. For example,excess prime mover power from primary energy source 104 can betransferred and stored. Similarly, when two or more Off Highway Vehicles200 operate in tandem and are electrically coupled, excess power fromone of the Off Highway Vehicles can be transferred and stored in energycapture and storage system 204. Also, a separate primary energy source102 (e.g., diesel generator, fuel cell, trolley line, etc.) can be usedto supply a charging voltage (e.g., a constant charging voltage) toenergy capture and storage system 204. Still another source of chargingis an optional off-vehicle charging source 220. For example, energycapture and storage system 204, can be charged by external chargingsource 220 such as a battery charger.

The energy capture and storage system 204 preferably includes at leastone of the following storage subsystems for storing the electricalenergy generated during the dynamic braking mode: a battery subsystem, aflywheel subsystem, an ultra-capacitor subsystem, and a fuel cell fuelgenerator (not shown). Other storage subsystems are possible.Ultra-capacitors are available from Maxwell Technologies. These storagesubsystems may be used separately or in combination. When used incombination, these storage subsystems can provide synergistic benefitsnot realized with the use of a single energy storage subsystem. Aflywheel subsystem, for example, typically stores energy relatively fastbut may be relatively limited in its total energy storage capacity. Abattery subsystem, on the other hand, often stores energy relativelyslowly but can be constructed to provide a relatively large totalstorage capacity. Hence, a flywheel subsystem may be combined with abattery subsystem wherein the flywheel subsystem captures the dynamicbraking energy that cannot be timely captured by the battery subsystem.The energy thus stored in the flywheel subsystem may be thereafter usedto charge the battery. Accordingly, the overall capture and storagecapabilities are preferably extended beyond the limits of either aflywheel subsystem or a battery subsystem operating alone. Suchsynergies can be extended to combinations of other storage subsystems,such as a battery and ultra-capacitor in combination where theultra-capacitor supplies the peak demand needs. In the case where theprimary energy source 102 is a fuel cell, the energy capture and storagesystem 204 may include an electrolysis system that generates hydrogenfrom the fuel cell wastewater. The stored hydrogen is provided to thefuel cell as an energy source for providing primary or secondary power.

It should be noted at this point that, when a flywheel subsystem isused, a plurality of flywheels is preferably arranged to limit oreliminate the gyroscopic effect each flywheel might otherwise have onthe Off Highway Vehicle and load vehicles. For example, the plurality offlywheels may be arranged On a six-axis basis to greatly reduce oreliminate gyroscopic effects. It should be understood, however, thatreference herein to a flywheel embraces a single flywheel or a pluralityof flywheels.

Referring still to FIG. 2, energy capture and storage system 204 notonly captures and stores electric energy generated in the dynamicbraking mode of the Off Highway Vehicle, it also supplies the storedenergy to assist the Off Highway Vehicle effort (i.e., to supplementand/or replace primary energy source power).

It should be understood that it is common for each Off Highway Vehicle200 to operate separately from other Off Highway Vehicles. However, twoor more Off Highway Vehicles could operate in tandem where they aremechanically and/or electrically coupled to operate together.Furthermore, another optional arrangement includes an Off HighwayVehicle that is mechanically coupled to a load vehicle. While FIG. 2illustrates a single Off Highway Vehicle, FIG. 3 illustrates an OffHighway Vehicle 200 operating in a tandem arrangement with optional loadvehicle 300. Load vehicle 300 may be a passive vehicle that is pulled orpushed by the Off Highway Vehicle 200 or optionally may include aplurality of load vehicle traction motors 308 that provide tractiveeffort to load vehicle wheels 318. The electrical power stored in energycapture and storage 204 may be selectively supplied (e.g., via tandemtraction bus 314) to the load vehicle traction motors 308 via loadvehicle traction bus 312. Thus, during times of increased demand, loadvehicle traction motors 308 augment the tractive power provided by OffHighway Vehicle traction motors 108. As another example, during timeswhen it is not possible to store more energy from dynamic braking (e.g.,energy storage system 204 is charged to capacity), efficiencyconsiderations may suggest that load vehicle traction motors 308 alsoaugment Off Highway Vehicle traction motors 108.

It should be appreciated that when energy capture and storage system 204drives load vehicle traction motors 308, additional circuitry willlikely be required. For example, if energy capture and storage system204 comprises a battery storing and providing a DC voltage, one or moreinverter drives 106 may be used to convert the DC voltage to a formsuitable for use by the load vehicle traction motors 308. Such drivesare preferably operationally similar to those associated with the OffHighway Vehicle.

Rather than, or in addition to, using the electrical power stored inenergy capture and storage 204 for powering load vehicle traction motors308, such stored energy may also be used to augment the electrical powersupplied to Off Highway Vehicle traction motors 108 (e.g., via line212).

Other configurations are also possible. For example, the Off HighwayVehicle itself may be configured, either during manufacturing or as partof a retrofit program, to capture, store, and regenerate excesselectrical energy, such as dynamic braking energy, excess primary energysource power or excess trolley line power. In another embodiment, anenergy capture and storage subsystem 306 may be located on some or allof the load vehicles attached to the Off Highway Vehicle. FIG. 3illustrates a load vehicle 300 equipped with a load vehicle energycapture and storage system 306 which receives load vehicle dynamicbraking power from load vehicle traction motor 308 via bus 312 duringdynamic braking. Such a load vehicle 300 may optionally include separatetraction motors 308. In each of the foregoing embodiments, the loadvehicle energy capture and storage subsystem 306 can include one or moreof the subsystems previously described.

When a separate load vehicle 300 is used, the load vehicle-300 and theOff Highway Vehicle 200 are preferably mechanically coupled viamechanical linkage 316 and electrically coupled via tandem traction bus314 such that dynamic braking energy from the Off Highway Vehicletraction motors 108 and/or from optional load vehicle traction motors308 is stored in energy capture and storage system 206 on board the OffHighway Vehicle and/or is stored in load vehicle capture and storagesystem 306 on the load vehicle 300. During motoring operations, thestored energy in the energy capture and storage system in one or theother or both the Off Highway Vehicle 200 and the load vehicle 300 isselectively used to propel Off Highway Vehicle traction motors 108and/or optional load vehicle traction motors 308. Similarly, when theOff Highway Vehicle primary power source 102 produces more power thanrequired for motoring, the excess prime mover power can bed stored inenergy capture and storage 204 and or load vehicle energy capture andstorage 306 for later use.

If load vehicle 300 is not electrically coupled to the Off HighwayVehicle (other than for standard control signals), the optional tractionmotors 308 on the load vehicle 300 can also be used in an autonomousfashion to provide dynamic braking energy to be stored in energy captureand storage 306 for later use. One advantage of such a configuration isthat load vehicle 202 can be coupled to a wide variety of Off HighwayVehicles.

It should be appreciated that when load vehicle traction motors 308operate in a dynamic braking mode, various reasons may counsel againststoring the dynamic braking energy in energy capture and storage 204and/or 306 (e.g., the storage may be full). Thus, it is preferable thatsome or all of the dynamic braking energy generated by the load vehicletraction motors 308 be dissipated by grids 310 associated with loadvehicle 300, or transferred to Off Highway Vehicle 200 to be dissipatedby grids 110 (e.g., via tandem traction bus 316).

It should also be appreciated that load vehicle energy capture andstorage system 306 may be charged from an external charging source 326when such a charging source is available.

The embodiment of FIG. 3 will be further described in terms of onepossible operational example. It is to be understood that thisoperational example does not limit the invention. The Off HighwayVehicle system 200 is configured in tandem including an Off HighwayVehicle 200 and a load vehicle 300. Tractive power for the Off HighwayVehicle 200 is supplied by a plurality of Off Highway Vehicle tractionmotors 108. In one embodiment, the Off Highway Vehicle 200 has fourwheels 109, each pair corresponds to an axle pair as depicted as an:optional embodiment of FIG. 3 as 109A and 109B. Each wheel 109A and 109Bincludes a separate Off Highway Vehicle traction motor 108A and 108B,and each traction motor 108A and 108B is an AC traction motor. In oneembodiment, each of the two rear wheels 109A has a separate Off HighwayVehicle traction motor 108A and operates as pair of wheels 109A on acommon axle, or axle-equivalent (illustrated as a single wheel 109A inFIG. 3). However, the wheels 109A may or may not be actually connectedby a common axle, as such an axle-equivalent. In fact, in oneembodiment, each wheel 109 is mount by a separate half-axle. The OffHighway Vehicle 200 includes a primary energy source 102 that drives anelectrical power system. In one embodiment, the primary energy source isa diesel engine drives an alternator/rectifier 104, that comprises asource of prime mover electrical power (sometimes referred to astraction power or primary power). In this particular embodiment, theprime mover electrical power is DC power that is converted to AC powerfor use, by the traction motors. More specifically, one or moreinverters (e.g., inverter 106) receives the prime mover electrical powerand selectively supply AC power to the plurality of Off Highway Vehicletraction motors 108 to propel the Off Highway Vehicle. In anotherembodiment, the primary energy source 102 is a fuel cell. The fuel cellgenerates DC prime mover power and selectively supplies the DC primarymover power to a DC-to-DC converter 302 as shown in FIG. 3. In yetanother embodiment, the Off Highway Vehicle 200 may utilize a trolleyline (not shown) as the primary energy source, or as a secondary energysource that supplements the primary energy source when the Off HighwayVehicle is traversing an inclined travel path, e.g., trolley assist.Thus, Off Highway Vehicle traction motors 108 propel the Off HighwayVehicle in response to the prime mover electrical power.

Each of the plurality of Off Highway Vehicle traction motors 108 ispreferably operable in at least two operating modes, a motoring mode anda dynamic braking mode. In the motoring mode, the Off Highway Vehicletraction motors 108 receive electrical power (e.g., prime moverelectrical power via inverters) to propel the Off Highway Vehicle 200.As described elsewhere herein, when operating in the dynamic brakingmode, the traction motors 108 generate electricity. In the embodiment ofFIG. 3, load vehicle 300 is constructed and arranged to selectivelycapture and store a portion of the electricity generated by the tractionmotors 308 and/or 108 during dynamic braking operations. This isaccomplished by energy capture and storage system 204 and/or 306. Thecaptured and stored electricity is selectively used to provide asecondary source of electric power. This secondary source of electricpower may be used to selectively supplement or replace the prime moverelectrical power (e.g., to help drive one or more Off Highway Vehicletraction motors 108) and/or to drive one or more load vehicle tractionmotors 308. In the latter case, load vehicle traction motors 308 and OffHighway Vehicle traction motors 108 cooperate to propel the tandem OffHighway Vehicle 200 and load vehicle 300.

Advantageously, load vehicle energy capture and storage 306 can storedynamic braking energy without any electrical power transfer connectionwith the primary Off Highway Vehicle. In other words, energy capture andstorage 306 can be charged without an electrical coupling such as tandemtraction bus 314. This is accomplished by operating the Off HighwayVehicle primary power source 320 to provide motoring power to OffHighway Vehicle traction motors 308 while operating load vehicle 300 ina dynamic braking mode. For example, the Off Highway Vehicle primarypower source 102 may be operated at a relatively high power settingwhile load vehicle traction motors 308 are configured for dynamicbraking. Energy from the dynamic braking process can be used to chargeenergy capture and storage 306. Thereafter, the stored energy can beused to power load vehicle traction motors 308 to provide additionalmotoring power to the tandem Off Highway Vehicle 200 and load vehicle300.

Referring again to FIG. 3 is another optional embodiment of hybridenergy Off Highway Vehicle system 300 configured with a fuel cell with aseparate load vehicle. This embodiment includes a fuel cell as primarypower source 102 that drives DC-to-DC converter 302. Converter 302provides DC power to inverter that provides primary tractive power. Inanother embodiment, where the traction motor 108 is a DC traction motor,the converter may provide tractive DC power directly to the DC tractionmotor 108 via traction bus 112.

Referring again to FIG. 3, another optional embodiment includes a loadvehicle configured with a load vehicle power source 320. Load vehiclepower source could be any type of power source as described above forthe Off Highway Vehicle 200. In one embodiment, load vehicle powersource 320 is a fuel cell that generates a constant source of DCelectrical energy. The DC electrical energy that is generated by thefuel cell is converted by a DC-to-DC converter 322 and provided to anInverter 324 for the provision of load vehicle primary power. In thisembodiment, load vehicle primary power may be provided by load vehiclebus 312 to the load vehicle traction motor 308, to the Off HighwayVehicle traction motors 108, to load vehicle energy capture and storagesystem 306, or to Off Highway Vehicle energy capture and storage system204. In this embodiment, the load vehicle power-source 320, the powerconverter 322, the converter 324 and/or the load vehicle energy captureand storage system 306 may be operable in response to a load vehicleenergy management system (not shown) or to the energy management system206 of the coupled Off Highway Vehicle via a energy managementcommunication link 328. Such an energy management communication link 328may be a wired communication link or a wireless communication link.

FIG. 4 is a system-level block diagram that illustrates aspects of oneembodiment of the energy storage and generation system. In particular,FIG. 4 illustrates an energy storage and generation system 400 suitablefor use with a hybrid energy Off Highway Vehicle system, such as hybridenergy Off Highway Vehicle system 200 or load vehicle system 300 (FIG.3). Such an energy storage and generation system 400 could beimplemented, for example, as part of a separate load vehicle (e.g.,FIGS. 2 and 3) and/or incorporated into an Off Highway Vehicle.

As illustrated in FIG. 4, a primary energy source 102 drives a primemover power source 104 (e.g., an alternator/rectifier converter). Theprime mover power source 104 preferably supplies DC power to an inverter106 that provides three-phase AC power to a Off Highway Vehicle tractionmotor 108. It should be understood, however, that the system 400illustrated in FIG. 4 can be modified to operate with DC traction motorsas well. Preferably, there is a plurality of traction motors 108, e.g.,one per traction wheel 109. In other words, each Off Highway Vehicletraction motor preferably includes a rotatable shaft coupled to theassociated wheel 109 for providing tractive power to the associatedwheel 109. Thus, each Off Highway Vehicle traction motor 108 providesthe necessary motoring force to an associated wheel 109 to cause the OffHighway Vehicle 200 to move. One arrangement includes a single wheel 109on the Off Highway-Vehicle to be equipped with a single traction motor108. Another embodiment is for two wheels 109 on opposing sides of thevehicle acting as an axle-equivalent, each equipped with a separatetraction motor 108.

When traction motors 108 are operated in a dynamic braking mode, atleast a portion of the generated electrical power is routed to an energystorage medium such as energy, storage 204. To the extent that energystorage 204 is unable to receive and/or store all of the dynamic brakingenergy, the excess energy is routed to braking grids 110 for dissipationas heat energy. Also, during periods when primary power source 102 isbeing operated such that it provides more energy than needed to drivetraction motors 108, the excess capacity (also referred to as excessprime mover electric power) may be optionally stored in energy storage204. Accordingly, energy storage 204 can be charged at times other thanwhen traction motors 108 are operating in the dynamic braking mode. Thisaspect of the system is illustrated in FIG. 4 by a dashed line 402.

The energy storage 204 of FIG. 4 is preferably constructed and arrangedto selectively augment the power provided to traction motors 108 or,optionally, to power separate traction motors 308 associated the loadvehicle 300. Such power may be referred to as secondary electric powerand is derived from the electrical energy stored in energy storage 204.Thus, the system 400 illustrated in FIG. 4 is suitable for use inconnection with an Off Highway Vehicle having an on-board energy captureand storage 204 and/or with a separate load vehicle 3001 equipped with aload vehicle-energy capture and storage 306.

FIG. 5 is a block diagram that illustrates aspects of one embodiment ofan energy storage and generation system 500 suitable for use with ahybrid energy Off Highway Vehicle system. The system 500 includes anenergy management system 206 for controlling the storage andregeneration of energy. Therefore, although FIG. 5 is generallydescribed with respect to an Off Highway Vehicle system, the energymanagement system 500 illustrated therein is not to be considered aslimited to Off Highway Vehicle applications.

Referring still to the exemplary embodiment illustrated in FIG. 5,system 500 preferably operates in the same general manner as system 400of FIG. 4; the energy management system 206 provides additionalintelligent control functions. FIG. 5 also illustrates an optionalenergy source 504 that is preferably controlled by the energy managementsystem 206. The optional energy source 504 may be a second energy source(e.g., another Off Highway Vehicle operating in tandem with the primaryOff Highway Vehicle) or a completely separate power source (e.g.,trolley line, or a wayside power source such as a battery charger) forcharging energy storage 204. In one embodiment, such a separate chargingpower source includes an electrical power station for charging an energystorage medium associated with a separate load vehicle (e.g., vehicle202 of FIG. 2) while stationary, or a system for charging the energystorage medium while the load vehicle is in motion. In one embodiment,optional energy source 504 is connected to a traction bus (notillustrated in FIG. 5) that also carries primary electric power fromprime mover power source 104.

As illustrated, the energy management system 206 preferably includes anenergy management processor 506, a database 508, and a positionidentification system 510, such as, for example, a global positioningsatellite system receiver (GPS) 510. The energy management processor 506determines present and anticipated Off Highway Vehicle positioninformation via the position identification system 510. In oneembodiment, energy management processor 506 uses this positioninformation to locate data in the database 508 regarding present and/oranticipated travel path topographic and profile conditions, sometimesreferred to as travel path situation information. Such travel pathsituation information may include, for example, travel path grade,travel-path elevation (e.g., height above mean sea level),travel-path-curve data, speed limit information, and the like. In thecase of a locomotive off highway vehicle, the travel path andcharacteristics are those of a railroad track. It is to be understoodthat such database information could be provided by a variety of sourcesincluding: an onboard database associated with processor 506, acommunication system (e.g., a wireless communication system) providingthe information from a central source, manual operator input(s), via oneor more travel path signaling devices, a combination of such sources,and the like. Finally, other vehicle information such as, the size andweight of the vehicle, a power capacity associated with the prime mover,efficiency ratings, present and anticipated speed present andanticipated electrical load, and so on may also be included in adatabase (or supplied in real or near real time) and used by energymanagement processor 506.

It should be appreciated that, in an alternative embodiment, energymanagement system 206 could be configured to determine power storage andtransfer requirements associated with energy storage 204 in a staticfashion. For example, energy management processor 506 could bepreprogrammed with any of the above information, or could use look-uptables based on past operating experience (e.g., when the vehiclereaches a certain point, it is nearly always necessary to storeadditional energy to meet an upcoming demand).

The energy management processor 506 preferably uses the present and/orupcoming travel path situation information, along with Off HighwayVehicle status information, to determine power storage and powertransfer requirements. Energy management processor 506 also determinespossible energy storage opportunities based on the present and futuretravel path situation information. For example, based on the travel pathprofile information, energy management processor 506 may determine thatit is more efficient to completely use all of the stored energy, eventhough present demand is low, because a dynamic braking region is comingup (or because the Off Highway Vehicle is behind schedule and isattempting to make up time). In this way, the energy management system206 improves efficiency by accounting for the stored energy before thenext charging region is encountered. As another example, energymanagement processor 506 may determine not to use stored energy, despitepresent demand, if a heavier demand is soon to be encountered in thetravel path.

Advantageously, energy management system 206 may also be configured tointerface with primary energy source controls. Also, as illustrated inFIG. 5, energy storage 204 may be configured to provide an intelligentcontrol interface with energy management system 206.

In operation, energy management processor 506 determines a power storagerequirement and a power transfer requirement. Energy storage 204 storeselectrical energy in response to the power storage requirement. Energystorage 204 provides secondary electric power (e.g. to a traction busconnected to inverters 106 to assist in motoring) in response to thepower transfer requirement. The secondary electric power is derived fromthe electrical energy stored in energy storage 204.

As explained above, energy management processor 506 preferablydetermines the power storage requirement based, in part, on a situationparameter indicative of a present and/or anticipated travel pathtopographic characteristic. Energy management processor 506 may alsodetermine the power storage requirement as a function of an amount ofprimary electric power available from the prime mover power source 104.Similarly, energy management processor 506 may determine the powerstorage requirement as function of a present or anticipated amount ofprimary electric power required to propel the Off Highway Vehicle.

Also, in determining the energy storage requirement, energy managementprocessor 506 preferably considers various parameters related to energystorage 204. For example, energy storage 204 will have a storagecapacity that is indicative of the amount of power that can be storedtherein and/or the amount of power that can be transferred to energystorage 204 at any given time. Another similar parameter relates to theamount of secondary electric power that energy storage 204 has availablefor transfer at a particular time.

As explained above, system 500 preferably includes a plurality ofsources for charging energy storage 204. These sources include dynamicbraking power, excess prime mover electric power, and external chargingelectric power. Preferably, energy management processor 506 determineswhich of these sources should charge energy storage 204. In oneembodiment, present or anticipated dynamic braking energy is used tocharge energy storage 204, if such dynamic braking energy is available.If dynamic braking energy is not available, either excess prime moverelectric power or external charging electric power is used to chargeenergy storage 204.

In the embodiment of FIG. 5, energy management processor 506 preferablydetermines the power transfer requirement as a function of a demand forpower. In other words, energy storage 204 preferably does not supplysecondary electric power unless traction motors 108 are operating in apower consumption mode (i.e., a motoring mode, as opposed to a dynamicbraking mode). In one form, energy management processor 506 permitsenergy storage 204 to supply secondary electric power to inverters 106until either (a) the demand for power terminates or (b) energy storage204 is completely depleted. In another form, however, energy managementprocessor 506 considers anticipated power demands and controls thesupply of secondary electric power from energy storage 204 such thatsufficient reserve power remains in energy storage 204 to augment primemover power source during peak demand periods. This may be referred toas a “look-ahead” energy management scheme.

In the look-ahead energy management scheme, energy management processor506 preferably considers various present and/or anticipated travel pathsituation parameters, such as those discussed above. In addition, energymanagement processor may also consider the amount of power stored inenergy storage 204, anticipated charging opportunities, and anylimitations on the ability to transfer secondary electric power fromenergy storage 204 to inverters 106.

FIGS. 6A-D, 7A-D, and 8A-E illustrate, in graphic form, aspects of threedifferent embodiments of energy management systems, suitable for usewith a hybrid energy vehicle, that could be implemented in a system suchas system 500 of FIG. 5. It should be appreciated that these figures areprovided for exemplary purposes and that, with the benefit of thepresent disclosure, other Variations are possible. It should also beappreciated that the values illustrated in these figures are included tofacilitate a detailed description and should not be considered in alimiting sense. It should be further understood that, the examplesillustrated in these figures relate to a variety of large Off HighwayVehicles, including loco motives, excavators and mine trucks and whichare generally capable of storing the electric energy generated duringthe operation of such vehicles. Some of these vehicles travel a known,repetitive or predictable course during operation. For example, alocomotive travels a known travel path, e.g., the railroad track. SuchOff Highway Vehicles include vehicles using DC and AC traction motordrives and having-dynamic braking/retarding capabilities.

There are four similar charts in each group of figures (FIGS. 6A-D,FIGS. 7A-D, and FIGS. 8A-D). The first chart in each group (i.e., FIGS.6A, 7A, and 8A) illustrates the required power for both motoring andbraking. Thus, the first chart graphically depicts the amount of powerrequired by the vehicle. Positive values on the vertical axis representmotoring power (horsepower); negative values represent dynamic brakingpower. It should be understood that motoring power could originate withthe prime mover (e.g., diesel engine, fuel cell or other primary energysource), or from stored energy (e.g., in an energy storage medium in aseparate vehicle), or from a combination of the prime mover and storedenergy. Dynamic braking power could be dissipated or stored in theenergy storage medium.

The horizontal axis in all charts reflects time in minutes. The timebasis for each chart in a given figure group are intended to be thesame. It should be understood, however, that other reference bases arepossible.

The second chart in each group of figures (i.e., FIGS. 6B, 7B, and 8B)reflects theoretical power storage and consumption. Positive valuesreflect the amount of power that, if power were available in the energystorage medium, could be drawn to assist in motoring. Negative valuesreflect the amount of power that, if storage space remains in the energystorage medium, could be stored in the medium. The amount of power thatcould be stored or drawn is partially a function of the converter andstorage capabilities of a given vehicle configuration. For example, theenergy storage medium will have some maximum/finite capacity. Further,the speed at which the storage medium is able to accept or supply energyis also limited (e.g., batteries typically charge slower than flywheeldevices). Other variables also affect energy storage. These variablesinclude, for example, ambient temperature, the size and length of anyinterconnect cabling, current and voltage limits on dc-to-dc convertersused for battery charging, power ratings for an inverter for a flywheeldrive, the charging and discharging rates of a battery, or a motor/shaftlimit for a flywheel drive. The second chart assumes that the maximumamount of power that could be transferred to or from the energy storagemedium at a given time is 500 h.p. Again, it should be understood thatthis 500 h.p. limit is included for exemplary purposes. Hence, thepositive and negative limits in any given system could vary as afunction of ambient conditions, the state and type of the energy storagemedium, the type and limits of energy conversion equipment used, and thelike.

The third chart in each figure group (i.e., FIGS. 6C, 7C, and 8C)depicts a power transfer associated with the energy storage medium. Inparticular, the third chart illustrates the actual power beingtransferred to and from the energy storage medium versus time. The thirdchart reflects limitations due to the power available for storage, andlimitations due to the present state of charge/storage of the energystorage medium (e.g., the speed of the flywheel, the voltage in anultra-capacitor, the charge in the battery, and the like).

The fourth chart in each figure group (i.e., FIGS. 6D, 7D, and 8D)depicts actual energy stored. In particular, the fourth chartillustrates the energy stored in the energy storage medium at anyparticular instant in time.

Referring first to FIGS. 6A-D, these figures reflect an energymanagement system that stores energy at the maximum rate possible duringdynamic braking until the energy storage medium is completely full. Inthis embodiment, all energy transfers to the storage medium occur duringdynamic braking. In other words, in the embodiment reflected in FIGS.6A-D, no energy is transferred to the energy storage medium from excessprime mover power available during motoring, or from other energysources. Similarly, energy is discharged, up to the maximum, rate,whenever there is a motor demand (limited to and not exceeding theactual demand) until the energy storage medium is completelydischarged/empty. FIGS. 6A-D assume that the energy storage medium iscompletely discharged/empty at time 0.

Referring now specifically to FIG. 6A, as mentioned above, the exemplarycurve identified therein illustrates the power required (utilized) formotoring and dynamic braking. Positive units of power reflect whenmotoring power is being applied to the wheels 109 of the vehicle (e.g.,one or more traction motors are driving Off Highway Vehicle wheels).Negative units of power reflect power generated by dynamic braking.

FIG. 6B is an exemplary curve that reflects power transfer limits.Positive values reflect the amount of stored energy that would be usedto assist in the motoring effort, if such energy were available.Negative units reflect the amount of dynamic braking energy that couldbe stored in the energy storage medium if the medium were able to acceptthe full charge available. In the example of FIG. 6B, the energyavailable for storage at any given time is illustrated as being limitedto 500 units (e.g., horsepower). As explained above, a variety offactors limit the amount of power that can be captured and transferred.Thus, from about 0 to 30 minutes, the Off Highway Vehicle requires lessthan 500 h.p. If stored energy were available, it could be used toprovide all of the motoring power. From about 30 minutes to about 65 or70 minutes, the Off Highway Vehicle requires more than 500 h.p. Thus, ifstored energy were available, it could supply some (e.g., 500 h.p.) butnot all of the motoring power. From about 70 minutes to about 75 minutesor so, the Off Highway Vehicle is in a dynamic braking mode andgenerates less than 500 h.p. of dynamic braking energy. Thus, up to 500h.p. of energy could be transferred to the energy storage medium, if themedium retained sufficient capacity to store the energy. At about 75minutes, the dynamic braking process generates in excess of 500 h.p.Because of power transfer limits, only up to 500 h.p. could betransferred to the energy storage medium (again, assuming that storagecapacity remains); the excess power would be dissipated in the brakinggrids. It should be understood that FIG. 6B does not reflect the actualamount of energy transferred to or from the energy storage medium. Thatinformation is depicted in FIG. 6C.

FIG. 6C is reflects the power transfer to/from the energy storage mediumat any given instant of time. The example shown therein assumes that theenergy storage medium is completely empty at time 0. Therefore, thesystem cannot transfer any power from the storage at this time. During afirst time period A (from approximately 0-70 minutes), the vehicle ismotoring (see FIG. 6A) and no power is transferred to or from the energystorage. At the end of the first time period A, and for almost 30minutes thereafter, the vehicle enters a dynamic braking phase (see FIG.6A). During this time, power from the dynamic braking process isavailable for storage (see FIG. 6B).

During a second time period B (from approximately-70-80 minutes),dynamic braking energy is transferred to the energy storage medium atthe maximum rate (e.g., 500 units) until the storage is full. Duringthis time there is no motoring demand to deplete the stored energy.Thereafter, during a third time period C (from approximately 80-105minutes) the storage is full. Consequently, even though the vehicleremains in the dynamic braking mode or is coasting (see FIG. 6A), noenergy is transferred to or from the energy storage medium during timeperiod C.

During a fourth time period D (from approximately 15-0120 minutes), thevehicle resumes motoring. Because energy is available in the energystorage medium, energy is drawn from the storage and used to assist themotoring process. Hence, the curve illustrates that energy is beingdrawn from the energy storage medium during the fourth time period D.

At approximately 120 minutes, the motoring phase ceases and, shortlythereafter, another dynamic braking phase begins. This dynamic brakingphase reflects the start of a fifth time period E that lasts fromapproximately 125-145 minutes. As can be appreciated by viewing thecurve during the fifth time period E, when the dynamic braking phaseends, the energy storage medium is not completely charged.

Shortly before the 150-minute point, a sixth time period F begins whichlasts from approximately 150-170 minutes. During this time period andthereafter (see FIG. 6A), the vehicle is motoring. From approximately150-170 minutes, energy is transferred from the energy storage medium toassist in the motoring process. At approximately 170 minutes, however,the energy storage is completely depleted. Accordingly, fromapproximately 170-200 minutes (the end of the sample window), no energyis transferred to or from the energy storage medium.

FIG. 6D illustrates the energy stored in the energy storage medium ofthe exemplary embodiment reflected in FIGS. 6A-D. Recall that in thepresent example, the energy storage medium is assumed to be completelyempty/discharged at time 0. Recall also that the present example assumesan energy management system that only stores energy from dynamicbraking. From approximately 0-70 minutes, the vehicle is motoring and noenergy is transferred to or from the energy storage medium. Fromapproximately 70-80 minutes or so, energy from dynamic braking istransferred to the energy storage medium until it is completely full. Atapproximately 105 minutes, the vehicle begins another motoring phase andenergy is drawn from the energy storage medium until about 120 minutes.At about 125 minutes, energy from dynamic braking is again transferredto the energy storage medium during another dynamic braking phase. Atabout 145 minutes or so, the dynamic braking phase ends and storageceases. At about 150 minutes, energy is drawn from the energy storagemedium to assist in motoring until all of the energy has been depletedat approximately 170 minutes.

FIGS. 7A-D correspond to an energy management system that includes a“look-ahead” or anticipated needs capability. This embodiment appliesparticularly when the travel path of the Off Highway Vehicle is known oris planned. Such a system is unlike the system reflected in FIGS. 6A-D,which simply stores dynamic braking energy when it can, and uses storedenergy to assist motoring whenever such stored energy is available. Theenergy management system reflected by the exemplary curves of FIGS. 7A-Danticipates when the prime mover cannot produce the full requireddemand, or when it may be less efficient for the prime mover to producethe full required demand. As discussed elsewhere herein, the energymanagement system can make such determinations based on, for example,known present position, present energy needs, anticipated future travelpath topography, anticipated future energy needs, present energy storagecapacity, anticipated energy storage opportunities, and likeconsiderations. The energy management system depicted in FIGS. 7A-D,therefore, preferably prevents the energy storage medium from becomingdepleted below a determined minimum level required to meet futuredemands.

By way of further example, the system reflected in FIGS. 7A-D ispremised on a Off Highway Vehicle having a primary energy source thathas a “prime mover limit” of 4,000 h.p. Such a limit could exist forvarious factors. For example, the maximum rated output could be 4,000h.p., or operating efficiency considerations may counsel againstoperating the primary power source above 4,000 h.p. It should beunderstood, however, that the system and figures are intended to reflectan exemplary embodiment only, and are presented herein to facilitate adetailed explanation of aspects of an energy management system suitablefor use with off-highway hybrid energy vehicles such as, for example,the Off Highway Vehicle system illustrated in FIG. 2.

Referring now to FIG. 7A, the exemplary curve illustrated thereindepicts the power required for motoring (positive) and braking(negative). At approximately 180 minutes, the motoring demand exceeds4,000 h.p. Thus, the total demand at that time exceeds the 4,000 h.p.operating constraint for the primary energy source. The “look-ahead”energy management system reflected in FIGS. 7A-D, however, anticipatesthis upcoming need and ensures that sufficient secondary power isavailable from the energy storage medium to fulfill the energy needs.

One way for the energy management system to accomplish this is to lookahead (periodically or continuously) to the upcoming travel path/courseprofile (e.g., incline/dec line, length of incline/decline, and thelike) for a given time period (also referred to as a look-ahead window).In the example illustrated in FIGS. 7A-D, the energy management systemlooks ahead 200 minutes and then computes energy needs/requirementsbackwards. The system determines that, for a brief period beginning at180 minutes, the primary energy source would require more energy thanthe limit.

FIG. 7B is similar to FIG. 6B. FIG. 7B, however, also illustrates thefact that the energy storage medium is empty at time 0 and, therefore,there can be no power transfer from the energy storage medium unless anduntil it is charged. FIG. 7B also reflects a look ahead capability.

Comparing FIGS. 6A-D with FIGS. 7A-D, it is apparent how the systemsrespectively depicted therein differ. Although the required power is thesame in both examples (see FIGS. 6A and 7A), the system reflected inFIGS. 7A-D prevents complete discharge of the energy storage mediumprior to the anticipated need at 180 minutes. Thus, as can be seen inFIGS. 7C and 7D, prior to the 180 minute point, the system briefly stopstransferring stored energy to assist in motoring, even though additionalstored energy remains available. The additional energy is thereaftertransferred, beginning at about 180 minutes, to assist the prime moverwhen the energy demand exceeds 4,000 h.p. Hence, the system effectivelyreserves some of the stored energy to meet upcoming demands that exceedthe desired limit of the prime mover.

It should be understood and appreciated that the energy available in theenergy storage medium could be used to supplement driving tractionmotors associated with the prime mover, or could also be used to driveseparate traction motors (e.g., on a load vehicle). With the benefit ofthe present disclosure, an energy management system accommodating avariety of configurations is possible.

FIGS. 8A-E reflect pertinent aspects of another embodiment of an energymanagement system suitable for use in connection with Off HighwayVehicle energy vehicles. The system reflected in FIGS. 8A-E includes acapability to store energy from both dynamic braking and from the primemover or another charging power source. For example, a given powersource may operate most efficiently at a given power setting (e.g.,4,000 h.p.). Thus, it may be more efficient to operate the power sourceat 4,000 h.p. at certain times, even when actual motoring demand fallsbelow that level. In such cases, the excess energy can be transferred toan energy storage medium.

Thus, comparing FIGS. 8A-D with FIGS. 6A-D and 7A-D, the differencesbetween the systems respectively depicted therein are apparent.Referring specifically to FIGS. 8A and 8D, from about 0-70 minutes, themotoring requirements (FIG. 8A) are less than the exemplary optimal4,000 h.p. setting. If desirable, the power source could be run at 4,000h.p. during this time and the energy storage medium could be charged. Asillustrated, however, the energy management system determines that,based on the upcoming travel path profile and anticipated dynamicbraking period(s), an upcoming dynamic braking process will be able tofully charge the energy storage medium. In other words, it is notnecessary to operate the primary energy source at 4,000 h.p. and storethe excess energy in the energy storage medium during this time becausean upcoming dynamic braking phase will supply enough energy to fullycharge the storage medium. It should be understood that the system couldalso be designed in other ways. For example, in another configurationthe system always seeks to charge the storage medium whenever excessenergy could be made available.

At approximately 180 minutes, power demands will exceed 4,000 h.p. Thus,shortly-before that time (while motoring demand is less than 4,000h.p.), the primary energy source can be operated at 4,000 h.p., with theexcess energy used to charge the energy storage medium to ensuresufficient energy is available to meet the demand at 180 minutes. Thus,unlike the systems reflected in FIGS. 6D and 7D, the system reflected inFIG. 8D provides that, for a brief period prior to 180 minutes, energyis transferred to the energy storage medium from the prime mover, even,though the vehicle is motoring (not braking).

FIG. 8E illustrates one way that the energy management system canimplement the look-ahead capability to control energy storage andtransfer in anticipation of future demands. FIG. 8E assumes a systemhaving a 200 minute look-ahead window. Such a look-ahead window ischosen to facilitate an explanation of the system and should not beviewed in a limiting sense. Beginning at the end of the window (200minutes), the system determines the power/energy demands at any givenpoint in time. If the determined demand exceeds the prime mover'scapacity or limit, the system continues back and determinesopportunities when energy can be stored, in advance of the determinedexcess demand period, and ensures that sufficient energy is storedduring such opportunities.

Although FIGS. 6A-D, 7A-D, and 8A-E have been separately described, itshould be understood that the systems reflected therein could beembodied in a single energy management system. Further, the look-aheadenergy storage and transfer capability described above could beaccomplished dynamically or in advance. For example, in one form, anenergy management processor (see FIG. 5) is programmed to compared thevehicle's present position with upcoming travel path/coursecharacteristics in real or near real time. Based on such dynamicdeterminations, the processor then determines how to best manage theenergy capture and storage capabilities associated with the vehicle in amanner similar to that described above with respect to FIGS. 7A-D and8A-E. In another form, such determinations are made in advance. Forexample, an off vehicle planning computer may be used to plan a routeand determine energy storage and transfer opportunities based on adatabase of known course information and projected conditions such as,for example, vehicle speed, weather conditions, and the like. Suchpre-planned data would thereafter be used by the energy managementsystem to manage the energy capture and storage process. Look-aheadplanning could also be done based on a route segment or an entire route.In some Off Highway Vehicle applications; such as a mine truck orexcavator, the travel path may be substantially the same on a day-to-daybasis, but may change on a weekly or monthly basis as the mine is workedand the travel path changes to adapt to the mine configuration. In thesecases, look-ahead planning may be changed as changes to the travel pathoccur.

It should further be understood that the energy management system andmethods described herein may be put into practice with a variety ofvehicle configurations. The energy management systems and methodsdescribed herein may be employed as part of an Off Highway Vehicle inwhich the energy storage medium is included as part of the vehicleitself. In other embodiments, such systems and methods could bepracticed with a Off Highway Vehicle having a separate load vehicleconfigured to house an external energy capture and storage medium. Asanother example, the energy management systems and methods hereindescribed could be employed with a Off Highway Vehicle having a separateload vehicle that employs its own traction motors. Other possibleembodiments and combinations should be appreciated from the presentdisclosure and need not be recited in additional detail herein.

FIGS. 9A-9G are electrical schematics illustrating several differentembodiments of an electrical system suitable for use in connection witha hybrid energy Off Highway Vehicle. In particular, the exemplaryembodiments illustrated in these figures relate to a hybrid energy OffHighway Vehicle system. It should be understood that the embodimentsillustrated in FIGS. 9A-9G could be incorporated in a plurality ofconfigurations, including those already discussed herein (e.g., a OffHighway Vehicle with a separate load vehicle, a Off Highway Vehicle witha self-contained hybrid-energy system, an autonomous load vehicle, andthe like). Other vehicles like off highway dump trucks for mining usethe same type of configuration using one, two or four traction motors,one per each driving wheel 109.

FIG. 9A illustrates an electrical schematic of a Off Highway Vehicleelectrical system having a energy capture and storage medium suitablefor us in connection with aspects of the systems and methods disclosedherein. The particular energy storage element illustrated in FIG. 9Acomprises a battery storage 902. The battery storage 902 is preferablyconnected directly across the traction bus (DC bus 122). In thisexemplary embodiment, an auxiliary power drive 904 is also connecteddirectly across DC bus 122. The power for the auxiliaries is derivedfrom DC bus 122, rather than a separate bus.

It should be appreciated that more than one type of energy storageelement may be employed in addition to battery storage 902. For example,an optional flywheel storage element 906 can also be connected inparallel with battery storage 902. The flywheel storage 906 shown inFIG. 9A is preferably powered by an AC motor or generator connected toDC bus 122 via an inverter or converter. Other storage elements such as,for example, capacitor storage devices (including ultra-capacitors) andadditional battery storages (not shown) can also be connected across theDC bus and controlled using choppers and/or converters and the like. Itshould be understood that although battery storage 902 is schematicallyillustrated as a single battery, multiple batteries or battery banks maylikewise be employed.

In operation, the energy storage elements (e.g., battery storage 902and/or any optional energy storage elements such as flywheel 906) arecharged directly during dynamic braking operations. Recall that, duringdynamic braking, one or more of the traction motor subsystems (e.g.,124A-124B) operate as generators and supply dynamic braking electricpower that is carried on DC bus 122. Thus, all or a portion of thedynamic braking electric power carried on DC bus 122 may be stored inthe energy storage element because the power available on the busexceeds demand. When the power source is motoring, the battery (and anyother optional storage element) is permitted to discharge and provideenergy to DC bus 122 that can be used to assist in driving the tractionmotors. This energy provided by the storage element may be referred toas secondary electric power. Advantageously, because the auxiliaries arealso driven by the same bus in this configuration, the ability to takepower directly from DC bus 122 (or put power back into bus 122) isprovided. This helps to minimize the number of power conversion stagesand associated inefficiencies due to conversion losses. It also reducescosts and complexities.

In an alternative embodiment, a fuel cell provides all or a portion ofthe primary power. In this embodiment, the energy storage device mayinclude an electrolysis or similar fuel cell energy source generation.As one example, the energy generated during dynamic braking powerselectrolysis to create hydrogen from water, one water source being thewaster water created by the fuel cell during prime energy generation.The generated hydrogen is stored and is used as a fuel for the primarypower source, the fuel cell.

It should be appreciated that the braking grids may still be used todissipate all or a portion of the dynamic braking electric powergenerated during dynamic braking operations. For example, an energymanagement system is to preferably used in connection with the systemillustrated in FIG. 9A. Such an energy management system is configuredto control one or more of the following functions: primary energygeneration, energy storage; stored energy usage; and energy dissipationusing the braking grids. It should further be appreciated that thebattery storage (and/or any other optional storage element) mayoptionally be configured to store excess prime mover electric power thatis available on the traction bus.

Those skilled in the art should appreciate that certain circumstancespreclude the operation of a diesel engine or fuel cell operating as theprimary energy source when the Off Highway Vehicle needs to be moved.For example, the engine or fuel cell may not be operable. As anotherexample, various rules and concerns may prevent the operation of adiesel engine inside buildings, yards, maintenance facilities, mines ortunnels. In such situations, the Off Highway Vehicle may be moved usinga fuel cell or stored secondary power. Advantageously, various hybridenergy Off Highway Vehicle configurations disclosed herein permit theuse of stored power for battery jog operations directly. For example,the battery storage 902 of FIG. 9A can be used for battery jogoperations. Further, the prior concept of battery jog operationssuggests a relatively short time period over a short distance. Thevarious configurations disclosed herein permit jog operations for muchlonger time periods and over much longer distances.

FIG. 9B illustrates a variation of the system of FIG. 9A. A primarydifference between FIGS. 9A and 9B is that the system shown in FIG. 9Bincludes chopper circuits DBC1 and DBC2 connected in series with thebraking grids. The chopper circuits DBC1 and DBC2 allow fine control ofpower dissipation through the grids that, therefore, provides greatercontrol over the storage elements such as, for example, battery storage902. In one embodiment, chopper circuits DBC1 and DBC2 are controlled byan energy management system (see FIG. 5). It should also be appreciatedthat chopper circuits DBC1 and DBC2, as well as any optional storagedevices added to the circuit (e.g., flywheel storage 906), could also beused to control transient power. In some embodiments, a combination ofdynamic braking contactors and chopper circuits may be utilized.

In the configuration of FIG. 9A, the dynamic braking contactors (e.g.,DB1, DB2) normally only control the dynamic braking grids in discreteincrements. Thus, the power flowing into the grids is also in discreteincrements (assuming a fixed DC voltage). For example, if each discreteincrement is 1,000 h.p., the battery storage capability is 2,000 h.p.,and the braking energy returned is 2,500 h.p., the battery cannot acceptall of the braking energy. As such, one string of grids is used todissipate 1,000 h.p., leaving 1,500 h.p. for storage in the battery. Byadding choppers DBC1, DBC2, the power dissipated in each grid string canbe more closely controlled, thereby storing more energy in the batteryand improving efficiency. In the foregoing example, choppers DBC1 andDBC2 can be operated at complementary 50% duty cycles so that only 500h.p. of the braking energy is dissipated in the grids and 2,000 h.p. isstored in the battery.

FIG. 9C is an electrical schematic of a Off Highway Vehicle electricalsystem illustrating still another configuration for implementing anenergy storage medium. In contrast to the systems illustrated in FIGS.9A and 9B, the battery storage 902 of FIG. 9C is connected to DC bus 122by way of a dc-to-dc converter 910. Such a configuration accommodates agreater degree of variation between DC bus 122 voltage and the voltagerating of battery storage 902. Multiple batteries and/or DC storageelements (e.g., capacitors) could be connected in a similar manner.Likewise, chopper control, such as that illustrated in FIG. 9B could beimplemented as part of the configuration of FIG. 9C. It should befurther understood that the dc-to-dc converter 910 may be controlled viaan energy management processor (see FIG. 5) as part of an energymanagement (system and process that controls the storage andregeneration of energy in the energy storage medium.

In operation, the electric power carried on DC bus 122 is provided at afirst power level (e.g., a first voltage level). The dc-to-dc converter910 is electrically coupled to DC bus 122. The dc-to-dc converter 910receives the electric power at the first power level and converts it toa second power level (e.g., a second voltage level). In this way, theelectric power stored in battery storage 902 is supplied at the secondpower level. It should be appreciated that the voltage level on DC bus122 and the voltage supplied to battery storage 902 via dc-to-dcconverter 910 may also be at the same power level. The provision ofdc-to-dc converter 910, however, accommodates variations between theserespective power levels.

FIG. 9D is an electrical schematic of a Off Highway Vehicle electricalsystem that is similar to the system shown in FIG. 9C. One differencebetween these systems is that the auxiliary power subsystem 904reflected in FIG. 9D is connected to, DC bus 122 via a pair of dc-to-dcconverters 912 and 914. Such a configuration provides the advantage ofallowing the use of existing, lower voltage auxiliary drives and/ormotor drives having low insulation. On the other hand, in thisconfiguration, the auxiliary power traverses two power conversionstages. It should be understood that although FIG. 9D illustrates theauxiliaries as consuming power all of the time—notregenerating—bi-directional dc-to-dc converters can also be used inconfigurations in which it is desirable to have the auxiliariesregenerate power (see, for example, FIG. 9G). These dc-to-dc converters912 and 914 are preferably controlled via an energy management systemthat controls the storage and regeneration of energy in the energystorage medium.

FIG. 9E illustrates, in electrical schematic form, still anotherconfiguration of an energy storage medium. Unlike the examplesillustrated in FIGS. 9A-9D, however, the configuration of FIG. 9Eincludes a separate DC battery bus 922. The separate battery bus 922 iselectrically isolated from main DC bus 122 (the traction bus) by adc-to-dc converter 920 (also referred to as a two-stage converter).Accordingly, the power flow between the traction bus (DC bus 122), theenergy storage elements, and the auxiliaries preferably passes throughthe bi-directional dc-to-dc converter 920. In the configuration of FIG.9E, any additional storage elements (e.g., flywheels, capacitors, andthe like) are preferably connected across the DC battery bus 922, ratherthan across the main DC bus 122. The dc-to-dc converter 920 may becontrolled via an energy management system that controls the storage andregeneration of energy in the energy storage medium.

FIG. 9F reflects a variation of the configuration of FIG. 9E. In theconfiguration of FIG. 9F, any variable voltage storage elements (e.g.,capacitors flywheels, and the like) that are used in addition to battery906 are connected directly across main DC bus 122 (the traction bus).However, battery 906 remains connected across the isolated DC batterybus 922. Advantageously, in this configuration dc-to-dc converter 920matches the voltage level of battery storage 902 but avoids twoconversions of large amounts of power for the variable voltage storageelements. Like the other configurations, the configuration of FIG. 9Fmay be implemented in connection with an energy management system thatoversees and controls the storage and regeneration of energy in theenergy storage medium.

FIG. 9G reflects a variation of the configuration of FIG. 9F in whichonly the auxiliaries are connected to a separate auxiliary bus 930through two-stage converter 920. Accordingly, electric power carried onDC bus 122 is provided at a first power level and power carried on theauxiliary bus 930 is provided at a second power level. The first andsecond power levels may or may not be the same.

FIGS. 10A-10C are electrical schematics that illustrate additionalembodiments, including embodiments particularly suited for modifyingexisting AC Off Highway Vehicles. It should be understood, however, thatthe configurations illustrated and described with respect to FIGS.10A-10C are not limited to retrofitting existing Off Highway Vehicles.

FIG. 10A illustrates a variation of the embodiment illustrated in FIG.9C. The embodiment of FIG. 10A uses only battery storage devices anddoes not include a non-battery storage, such as optional flywheelstorage 906. In particular, FIG. 10A illustrates an embodiment having aconverter 1006 (e.g., a dc-to-dc converter) connected across DC bus 122.A battery storage element 1002 is connected to the converter 1006.Additional converters and battery storage elements may be added to thisconfiguration in parallel. For example, another converter 1008 may beconnected across DC bus 122 to charge another battery storage element1004. One of the advantages of the configuration of FIG. 10A is that itfacilitates the use of multiple batteries (or battery banks) havingdifferent voltages and/or charging rates.

In certain embodiments, power transfer between energy storage devices isfacilitated. The configuration of FIG. 10A, for instance, allows forenergy transfer between batteries 1002 and 1004 via the DC bus 122. Forexample, if during motoring operations, the primary power sourcesupplies 2,000 h.p. of power to the dc traction bus, the traction motorsconsume 2,000 h.p., and battery 1002 supplies 100 h.p. to the tractionbus (via converter 1006), the excess 100 h.p. is effectively transferredfrom battery 1002 to battery 1004 (less any normal losses).

The configuration illustrated in FIG. 10B is similar to that of FIG.10A, except that it uses a plurality of converters (e.g., converters1006, 1008) connected to the DC bus 122 to supply a common battery 1020(or a common battery bank). One of the advantages of the configurationof FIG. 10B is that it allows the use of relatively smaller converters.This may be particularly advantageous when retrofitting an existing OffHighway Vehicle that already has one converter. A similar advantage ofthis configuration is that it allows the use of higher capacitybatteries. Still another advantage of the configuration of FIG. 10B isthat it permits certain phase shifting operations, thereby reducing theripple current in the battery and allowing the use of smaller inductors(not shown). For example, if converters 1006 and 1008 are operated at1,000 Hz, 50% duty cycles, and the duty cycles are selected such thatconverter 1006 is on while converter 1008 is off, the converter effectis as if a single converter is operating at 2,000 Hz, which allows theuse of smaller inductors.

FIG. 10C an electrical schematic illustrating another embodiment that isparticularly well suited for retrofitting an existing Off HighwayVehicle to operate as a hybrid energy Off Highway Vehicle. Theconfiguration of FIG. 10C uses a double set of converters 1006, 1030 andone or more batteries 1020 (of the same or different voltage levels). Anadvantage of the system depicted in FIG. 10C is that the battery 1020can be at a higher voltage level than the DC bus 122. For example, ifthe converters 1006, 1008 illustrated in FIGS. 10A and 10B are typicaltwo quadrant converters, they will also have freewheeling diodesassociated therewith (not illustrated). If the voltage of battery 1002,1004 (FIG. 10A), or 1020 (FIG. 10B) exceeds the DC bus voltage, thebattery will discharge through the freewheeling diode. A doubleconverter, such as that illustrated in FIG. 10C, avoids this situation.One advantage of this capability is that the voltage level on the DC buscan be modulated to control power to the dynamic braking gridsindependently.

FIG. 11 is an electrical schematic that illustrates one way ofconnecting electrical storage elements. In particular, FIG. 11illustrates an electrical schematic of a system that may be used forretrofitting a prior art Off Highway Vehicle to operate as a hybridenergy Off Highway Vehicle, or for installing a hybrid energy system aspart of the original equipment during the manufacturing process. Theembodiment illustrated assumes an AC diesel electric Off Highway Vehiclewith four wheels, a pair of wheels located on two axle-equivalents. Twowheels 109 of a single axle-equivalent are driven by individual tractionmotor subsystems. However, in other embodiments all four wheels 109A and109B of the two axle-equivalents may be driven by four traction motorsubsystems, or any number of traction motors are envisioned consistentwith the current invention. For instance, while not commonplace for OffHighway Vehicles would be to have two wheels 109A on a single axle witha single traction motor subsystem for the single axle two wheelarrangement.

Typically, the primary energy source has extra capability (e.g., powercapacity) available in the majority of operating conditions. Such extracapability may be due to lower actual ambient conditions, as comparedwith the design criteria. For example, some Off Highway Vehicles aredesigned to operate-in-ambient temperatures of up to 60 degrees Celsius,which is well above typical operating conditions. Considerations otherthan thermal conditions may also result in extra capacity duringsignificant operating periods. In a typical Off Highway Vehicle, forinstance, the use of all of the traction motors may only be required forlow speed and when the Off Highway Vehicle operates in an adhesionlimited situation (poor tractive conditions). In such case, the weighton the driven wheels 109 determines the pulling power/tractive effort.Hence, all available wheel/motors need to be driven to obtain maximumtractive effort. This can be especially true if the Off Highway Vehicleis heavily loaded during poor tractive conditions (snow, mud, or wet).Such conditions may normally be present for only a fraction of theoperating time. During the majority of the operating time, all of thetraction motors/inverters are not fully utilized to supply tractiveeffort. Thus, for example, when retrofitting an existing prior art OffHighway Vehicle, or manufacturing a new Off Highway Vehicle, it ispossible to take advantage of this partial under utilization of thetraction motors/inverters.

By way of a specific example, the embodiment of FIG. 11 is configuredsuch that one of the two traction motor subsystems is connected to theenergy storage element 1102, through a transfer switch 1104 and aplurality of inductors 1110. More particularly, the traction motorsubsystem 124B includes an inverter 106B and a traction motor 1108B.Such a configuration is suited for retrofitting a single wheel 109 of anexisting prior art Off Highway Vehicle. It should be understood thatretrofitting a typical prior art Off Highway Vehicle requires theaddition of power conversion equipment and associated cooling devices.The space available for installing the retrofit equipment, however, isgenerally limited. Therefore, one of the advantages of the“single-wheel” configuration of FIG. 11 is that it tends to minimizeimpacts and makes retrofitting a more viable option. Similar advantages,however, may also be enjoyed When the hybrid energy system is installedas original equipment during manufacturing.

The transfer switch 1104 preferably comprises a three-phase set ofcontactors or a set of motorized contacts (e.g., bus bars) that connectinverter 106B to traction motor 1108B when all of the wheels 109A and109B are needed, and connects inverter 106B to inductors 1110 andbattery 1102 when battery charging or discharging is desired. Thus,transfer switch 1104 has a first connection state and a secondconnection state. In the first connection state, transfer switch, 1104connects inverter 106B to traction motor 1108B. In the second connectionstate, transfer switch connects inverter 106B to battery 1102.

Transfer switch 1104 is preferably controlled by a switch controller1120. In one form, the switch controller 1120 is a manualoperator-controlled switch that places transfer switch 1104 into thefirst or the second connection state. In another form, the switchcontroller reflects control logic that controls the connection state oftransfer switch 1104 in accordance with one operating scheme. Table I(below) is indicative of one such operating scheme. Other schemes arepossible. For example, in one embodiment, the transfer switch 1104 iscontrolled by the energy management processor 506 executing computerexecutable instructions such as described below in reference to FIG. 13.

Although FIG. 11 illustrates a three-phase connection between battery1102 and transfer switch 1104, it is not necessary that all three phasesbe used. For example, if the power requirement is relatively low, onlyone or two phases may be used. Similarly, three separate batteries couldbe independently connected (one to each phase), or one large batterycould be connected to two phases, with a relatively smaller batteryconnected to the third phase. Further, power transfer between multiplebatteries having different voltage potentials and/or capacities is alsopossible.

The configuration of FIG. 11 is especially advantageous in the contextof retrofitting existing Off Highway Vehicles because transfer switch1104 is believed to be much less expensive than adding additionalinverters and/or dc-to-dc converters. Such advantage, however, is notlimited to the retrofit context. Also, it should bet understood that theconfiguration of FIG. 11 is not limited to a single inverter pertransfer switch configuration.

FIG. 11 further illustrates an optional charging source 1130 that may beelectrically connected to DC traction bus 122. The charging source 1130may be, for example, another charging energy source or an externalcharger, such as that discussed in connection with FIG. 5.

The general operation of the configuration of FIG. 11 will be describedby reference to the connection states of transfer switch 1104. Whentransfer switch 1104 is in the first, switch state, the second wheel109B is selectively used to provide additional motoring or brakingpower. In this switch state, battery 1102 is effectively disconnectedand, therefore, neither charges nor discharges.

When the second wheel 109B is not needed, switch controller 1120preferably places transfer switch 1104 in the second connectionstate—battery 1102 is connected to inverter 106B. If, at this time, theother traction motor (e.g., traction motor 108A) is operating in adynamic braking mode, electrical energy is generated and carried on DCtraction bus 122, as described in greater detail elsewhere herein.Inverter 106B transfers a portion of this dynamic braking electricalenergy to battery 1102 for storage. If, on the other hand, the othertraction motor is operating in a motoring mode, inverter 106B preferablytransfers any electrical energy stored in battery 1102 onto DC tractionbus 122 to supplement the primary electric power supplied by prime moverpower source 104. Such electrical energy transferred from battery 1102to DC traction bus 122 may be referred to as secondary electric power.In one embodiment, inverter 106B comprises a chopper circuit forcontrolling the provision of secondary electric power to DC traction bus122 from battery 1102.

It should be understood, however, that battery 1102 can also be chargedwhen the other traction motors are not operating in a dynamic brakingmode. For example, the battery can be charged when transfer switch 1104is in the second connection state (battery 1102 is connected to inverter106B) and the other traction motors are motoring or idling if the amountof power drawn by the other traction motors is less than the amount ofprimary electric power carried on DC traction bus 122.

Advantageously, battery 1102 can also be charged using charging electricpower from optional energy source 1130. As illustrated in FIG. 11,optional energy source 1130 is preferably connected such that itprovides charging electric power to be carried on DC traction bus 122.When optional energy source 1130 is connected and providing chargingelectric power, switch controller 1120 preferably places transfer switch1104 in the second connection state. In this configuration, inverter106B transfers a portion of the electric power carried on DC tractionbus 122 to battery 1102 for storage. As such, battery 1102 may becharged from optional energy source 1130.

In summary, in the embodiment of FIG. 11, when transfer switch is in thesecond connection state, battery 1102 may be charged from dynamicbraking energy, from excess Off Highway Vehicle energy (i.e., when theother traction motors draw less power than the amount of primaryelectric power carried on DC traction bus 122), and/or from chargingelectric power from optional charging source 1130. When transfer switch1104 is in the second connection state and the other traction motordraws more power than the amount of primary electric power carried on DCtraction bus 122, inverter 106B transfers secondary electric power frombattery 1102 to DC traction bus 122 to supplement the primary electricpower. When transfer switch 1104 is in the first connection state,battery 1102 is disconnected and traction motor 1108B is operable toassist in motoring and/or dynamic braking. Table I summarizes one set ofoperating modes of the embodiment of FIG. 11.

TABLE I One Axle Two Axles Low Speed and Low Battery Fully Charged &Tractive Effort Settings Dynamic Braking High Speed Motoring No BatteryCharging & Motoring Battery Discharged & Motoring Very High SpeedDynamic Braking

While FIG. 11 illustrates an energy storage device in the form of abattery, other energy storage devices, such as flywheel systems orultra-capacitors, may also be employed instead of or in addition tobattery 1102. Further, it should be understood that the configuration ofFIG. 11 may be scaled. In other words, the configuration can be appliedto more than one axle.

Although the foregoing descriptions have often referred to AC OffHighway Vehicle systems to describe several pertinent aspects of thedisclosure, the invention should not be interpreted as being limited tosuch Off Highway Vehicle systems. For example, aspects of the presentdisclosure may be employed with diesel-electric, fuel cell, “allelectric,” third-rail, trolley or overhead powered Off Highway Vehicles.Further, aspects of the hybrid energy Off Highway Vehicle systems andmethods described herein can be used with Off Highway Vehicles using aDC generator rather than an AC alternator and combinations thereof.Also, the hybrid energy Off Highway Vehicle systems and methodsdescribed herein are not limited to use with AC traction motors. Asexplained elsewhere herein, the energy management system disclosedherein may be used in connection with locomotives, mine trucks, largeexcavators, etc.

In one embodiment, the energy management system 206 comprises a computerreadable medium, such as the energy management processor 506 havingcomputer executable instructions for controlling the operation of thehybrid energy railway vehicle 200. In particular, the energy managementprocessor can be configured to execute computer executable instructionsfor controlling the flow of electrical power among the primary electricpower source 102, the traction motors 108, the electric energy capturesystem 204, and each of the plurality of dynamic braking grid circuits110 during motoring, operating and braking the travel of the off highwayvehicle 200.

For example, referring now to FIG. 13, an exemplary block diagramillustrates an energy management processor 506 having computerexecutable instruction for controlling the transmission of power duringmotoring, operating and braking the travel of the off highway vehicle200. The processor 506 is connected to the primary energy source 162 andto the traction motors 108 (see FIG. 5) executes transmissioninstructions 1302 to control the transmission of electrical power to thetraction motor 1108B during motoring mode of the vehicle propulsionsystem, and to control the transmission of electrical power from thetraction motor 1108B when the traction motor 1108B is operating as agenerator in the dynamic braking mode. The processor 506 is alsoconfigured to execute transmission instructions 1302 to control thetransmission of electrical power to an energy storage element 1002 suchas described above in reference to FIG. 11. The processor 506 isconnected to one or more of the plurality of contactors (e.g., DB1-DB5shown in FIG. 1B or chopper circuits DBC1 and DBC2 shown in FIG. 9B) andexecutes dissipating instructions 1306 to control the switching of theplurality of power resistive elements between the positive and negativerails of the DC bus 122. As described above in reference to FIG. 11, atleast one of the traction motor subsystems is connected to the energystorage element 1102, through a power transfer switch 1104 and aplurality of inductors 1110. In this embodiment, the processor 506executes the transmission instructions 1302 to control the operation ofthe transfer switch 1104, and, thus control the flow of electrical powerto and from the energy storage element 1102.

Moreover, as described above in reference to FIG. 5, the energymanagement processor 506 can be programmed to compare the vehicle'spresent position with upcoming travel path/course data in the database508 to determine how to best manage the energy capture and storage. Morespecifically, the processor 506 is responsive to stored track topographydata and a train locator device, such as the position identificationsystem 510, locating a current position of the train to executedetermining instructions 1306 to determine the future train electricenergy requirements as a function of the track topography data and thecurrent position of the train. Thereafter, the transmission instructions1302 are responsive to the determined future energy requirements tocontrol the flow of electrical power among the primary electric powersource, the traction motors 108, the electric energy capture system 204,and each of the plurality of dynamic braking grid circuits 110 as afunction of the determined future train electric energy requirements.

It should be appreciated that the principles of the instant inventionsmay apply to any suitable computer equipment, such as other mainframes,minicomputers, microprocessors, microcontrollers, network servers,supercomputers, personal computer's, or workstations, as well as otherelectronics applications. Therefore, while the specification hereinfocuses on particular applications, it should be understood that theinstant inventions are not limited to the particular hardware designs,software designs, and communications protocols disclosed herein. Theinventions can also be embodied, in part, as computer readable code on acomputer readable medium. The computer readable medium is any datastorage device that can store data, which thereafter can be read by acomputer system. Examples of computer readable medium include read-onlymemory, random-access memory, CD-ROMs, DVDs, magnetic tape, optical datastorage devices. The computer readable medium can also be distributedover network coupled computer systems so that the computer readable codeis stored and executed in a distributed fashion.

Based on the foregoing specification, the inventions may be implementedusing computer programming or engineering techniques including computersoftware, firmware, hardware or any combination or subset thereof. Anysuch resulting program, having computer-readable code means, may beembodied or provided within one or more computer-readable media, therebymaking a computer program product, i.e., an article of manufacture,according to the invention. The computer readable media may be, forexample, a fixed (hard) drive, diskette, optical disk, magnetic tape,semiconductor memory such as read-only memory (ROM), etc., or anytransmitting/receiving medium such as the Internet or othercommunication network or link. The article of manufacture containing thecomputer code may be made and/or used by executing the code directlyfrom one medium, by copying the code from one medium to another medium,or by transmitting the code over a network.

An apparatus for making, using or selling the inventions may be one ormore processing systems including, but not limited to, a centralprocessing unit (CPU), memory, storage devices, communication links anddevices, servers, I/O devices, or any sub-components of one or moreprocessing systems, including software, firmware, hardware or anycombination or subset thereof, which embody the invention as set forthin the claims. User input may be received from the keyboard, mouse, pen,voice, touch screen, or any other means by which a human can input datato a computer, including through other programs such as applicationprograms.

One skilled in the art of computer science will be able to combine thesoftware created as described with appropriate general purpose orspecial purpose computer hardware to create a computer system orcomputer sub-system embodying the method of the invention.

It should be understood that the examples and embodiments describedherein are for illustrative purposes only and that various modificationsor changes in light thereof will be suggested to persons skilled in theart and are to be included within the spirit and purview of thisapplication and the scope of the appended claims.

As can now be appreciated, the hybrid energy systems and methods hereindescribed provide substantial advantages over the prior art. Suchadvantages include improved fuel efficiency, increased fuel range, andreduced emissions such as transient smoke. Other advantages includeimproved speed by the provision of an on-demand source of power for ahorsepower burst. Significantly, the hybrid energy Off Highway Vehiclesystem herein described may also be adapted for use with existing OffHighway Vehicle systems.

When introducing elements of the invention or embodiments thereof, thearticles “a”, “an”, “the”, and “said” are intended to mean that thereare one or more of the elements. The terms “comprising”, “including”,and “having” are intended to be inclusive and mean that there may beadditional elements other than the listed elements.

In view of the above, it will be seen that several aspects of theinvention are achieved and other advantageous results attained.

As various changes could be made in the above exemplary constructionsand methods without departing from the scope of the invention, it isintended that all matter contained in the above description or shown inthe accompanying drawings shall be interpreted as illustrative and notin a limiting sense. It is further to be understood that the stepsdescribed herein are not to be construed as necessarily requiring theirperformance in the particular order discussed or illustrated. It is alsoto be understood that additional or alternative steps may be employed.

1. A computerized system for operating a hybrid energy, electro-motive,self-powered railroad train, said railroad train including: at least onerailway vehicle supported on a plurality of wheels for engaging railroadrails; a vehicle propulsion system mechanically coupled to at least oneof the wheels of the railway vehicle: a primary electric power generatorcarried on the railroad vehicle for generating primary electrical powerto be supplied to the vehicle propulsion system, said vehicle propulsionsystem having a motoring mode in which the propulsion system isresponsive to electric power supplied to the propulsion system forgenerating mechanical energy that is applied to said wheel forpropelling the railroad vehicle, and said vehicle propulsion systemfurther having a dynamic braking mode in which the propulsion system isresponsive to mechanical energy from said wheel during dynamic brakingoperations of the railroad vehicle for generating dynamic brakingelectrical power; an electrical energy capture system carried on therailroad vehicle for storing electrical power generated on the train andfor discharging the stored electrical power to propel the railroadvehicle; a direct current (DC) bus for electrically connecting theprimary electric power generator, the vehicle propulsion system and theelectrical energy capture system; a plurality of dynamic brakingresistance grid circuits electrically connected to the vehiclepropulsion system for dissipating excess electrical power on therailroad vehicle, with each grid circuit including at least one dynamicbraking resistance grid and being connected to the DC bus; a pluralityof grid switching devices in the dynamic braking grid circuits, with atleast one grid switching device for each dynamic braking grid circuitfor controlling the flow of electrical power to the respectiveresistance grid; said computerized system comprising: a processorexecuting computer executable instructions for controlling flow ofelectrical power among the primary electric power generator, the vehiclepropulsion system, the electrical energy capture system, and each of theplurality of dynamic braking resistance grid circuits during motoring,operating and braking the travel of the railroad vehicle, said computerexecutable instructions including: transmission instructions forcontrolling the transmission of electrical power from the primaryelectric power generator to the DC bus, controlling the transmission ofelectrical power from the DC bus to the electrical energy capturesystem, and controlling the transmission of electrical power to the DCbus from the electrical energy capture system, said transmissioninstructions controlling during motoring, operating and braking thetravel of the railroad vehicle, wherein: said processor provides a firstcontrol signal to the electrical energy capture system to control theselective storing of electrical energy generated in the dynamic brakingmode and to control the selective providing of secondary electric powerto the vehicle propulsion system as a function of at least one of thefollowing: a travel path situation parameter, a manual operator input, asize or a weight of the railroad train, a power capacity associated withthe primary electric power generator, an efficiency rating of acomponent of the railroad train, a present speed of the railroadvehicle, an anticipated speed of the railroad vehicle, a presentelectrical load of the railroad vehicle, and an anticipated electricalload of the railroad vehicle; and said processor provides a secondcontrol signal to the primary electric power generator to control theselective supplying of primary electric power to the vehicle propulsionsystem as a function of at least one of the following: a travel pathsituation parameter, a manual operator input, a size or a weight of therailroad train, a power capacity associated with the primary electricpower generator, an efficiency rating of a component of the railroadtrain, a present speed of the railroad vehicle, an anticipated speed ofthe railroad vehicle, a present electrical load of the railroad vehicle,and an anticipated electrical load of the railroad vehicle; anddissipating instructions for controlling during braking the travel ofthe railroad vehicle the operation of each of the plurality of gridswitching devices in the dynamic braking resistance grid circuits tocontrol the flow of electrical power from the DC bus to the respectiveresistance grid, wherein the dissipating instructions control a dutycycle of at least one of the plurality of grid switching devices suchthat electrical power generated by the vehicle propulsion system thatthe electrical energy capture system is able to store is not dissipatedby the plurality of resistive grids.
 2. The computer executableinstructions of claim 1, wherein the transmission instructions controlthe transmission of electrical power to and from a traction motor, saidtraction motor connected to a vehicle wheel and operable as a motor inthe motoring mode of the vehicle propulsion system and as a generator inthe dynamic braking mode of the vehicle propulsion system, and whereinthe transmission instructions maximize the storage of excess electricalpower from the DC bus in the energy capture system during braking. 3.The computer executable instructions of claim 1, wherein thetransmission instructions control the transmission of electrical powerto and from a plurality of traction motors, wherein a pair of vehiclewheels is associated with each traction motor.
 4. The computerexecutable instructions of claim 1, wherein the transmissioninstructions control the operation of a power switching device in acircuit with the primary electric power generator, the vehiclepropulsion system, an electrical energy capture system, and each of theplurality of dynamic braking resistance grid to control the transmissionof electrical power among the primary electric power generator, thevehicle propulsion system, an electrical energy capture system, and eachof the plurality of dynamic braking resistance grid circuits.
 5. Thecomputer executable instructions of claim 1, wherein the railroadvehicle further comprises electrical connections for connecting the DCbus to an external source of electrical power, and wherein thetransmission instructions control the electrical connections toselectively connect the DC bus to an external source of electrical powerto control the transmission of electrical power from the external sourceof electrical power to the DC bus.
 6. The computer executableinstructions of claim 1, wherein the transmission instructions controlthe operation of an energy storage switching device in a circuit withthe DC bus and the electrical energy capture system to control the flowof electrical power to and from the electrical energy capture system,wherein the energy storage switching device comprises a contactorswitch.
 7. The computer executable instructions of claim 6, whereintransmission instructions control the operation of the energy storageswitching device to control the transmission of electrical power to anelectric storage battery.
 8. The computer executable instructions ofclaim 6, wherein transmission instructions control the operation of theenergy storage switching device to control the transmission ofelectrical power to a storage device selected from the group comprisingultra-capacitors, flywheel-generators, and fuel cells.
 9. The computerexecutable instructions of claim 1, wherein the train further includesan auxiliary electric power generator for generating auxiliaryelectrical power and electrically connected to the electrical energycapture system, and wherein the transmission instructions control thetransmission of electrical power from the auxiliary electric powergenerator.
 10. The computer executable instructions of claim 9, whereinthe train further comprises auxiliary electric power loads electricallyconnected to the auxiliary power generator, and wherein transmissioninstructions control the transmission of electrical power to theauxiliary electric power generator.
 11. The computer executableinstructions of claim 1, wherein the processor is operatively connectedto a computer readable medium storing track topography data and a trainlocator locating a current position of the train, and wherein thecomputer executable instructions further include determininginstructions for determining future train electric energy requirementsas a function of the track topography data and the current position ofthe train, said transmission instructions responsive to the determinedfuture energy requirements to control the flow of electrical power amongthe primary electric power generator, the vehicle propulsion system, theelectrical energy capture system, and each of the plurality of dynamicbraking resistance grid circuits as a function of the determined futuretrain electric energy requirements.
 12. The computer executableinstructions of claim 1, wherein at least one of the grid switchingdevices comprises an electronic power management chopper switch, andwherein the dissipating instructions control the operation of theelectronic power management chopper switch to control the flow ofelectrical power to the respective resistance grid.
 13. A computerizedsystem for operating a hybrid energy, electro-motive, self-poweredoff-highway load vehicle, said off-highway vehicle (OHV) including: aplurality of wheels for supporting and propelling the OHV, a vehiclepropulsion system mechanically coupled to at least one of the wheels ofthe OHV; a primary electric power generator carried on the OHV forgenerating primary electrical power to be supplied to the vehiclepropulsion system, said vehicle propulsion system having a motoring modein which the propulsion system is responsive to electric power suppliedto the propulsion system for generating mechanical energy that isapplied to said wheel for propelling the OHV, and said vehiclepropulsion system further having a dynamic braking mode in which thepropulsion system is responsive to mechanical energy from said wheelduring dynamic braking operations of the OHV for generating dynamicbraking electrical power; an electrical energy capture system carried onthe OHV for storing electrical power generated on the OHV and fordischarging the stored electrical power for use on the vehicle,including selectively using the stored electric power to propel the OHV;a direct current (DC) bus for electrically connecting the primaryelectric power generator, vehicle propulsion system and electricalenergy capture system; a plurality of dynamic braking resistance gridcircuits electrically connected to the vehicle propulsion system fordissipating excess electrical power on the OHV, with each grid circuitincluding at least one dynamic braking resistance grid and beingconnected to the DC bus; a plurality of grid switching devices in thedynamic braking resistance grid circuits, with at least one gridswitching device for each dynamic braking grid circuit for controllingthe flow of electrical power to the respective resistance grid; saidcomputerized system comprising: a processor executing computerexecutable instructions for controlling flow of electrical power amongthe primary electric power generator, the vehicle propulsion system, theelectrical energy capture system, and each of the plurality of dynamicbraking resistance grid circuits during motoring, operating and brakingthe travel of the OHV, said computer executable instructions including:transmission instructions for controlling the transmission of electricalpower from the primary electric power generator to the DC bus,controlling the transmission of electrical power from the DC bus to theelectrical energy capture system, and controlling the transmission ofelectrical power to the DC bus from the electrical energy capturesystem, said transmission instructions controlling during motoring,operating and braking the travel of the OHV, wherein: said processorprovides a first control signal to the electrical energy capture systemto control the selective storing of electrical energy generated in thedynamic braking mode and to control the selective providing of secondaryelectric power to the vehicle propulsion system as a function of atleast one of the following: a travel path situation parameter, a manualoperator input, a size or a weight of the OHV, a power capacityassociated with the primary electric power generator, an efficiencyrating of a component of the OHV, a present speed of the OHV, ananticipated speed of the OHV, a present electrical load of the OHV, andan anticipated electrical load of the OHV; and said processor provides asecond control signal to the primary electric power generator to controlthe selective supplying of primary electric power to the vehiclepropulsion system as a function of at least one of the following: atravel path situation parameter, a manual operator input, a size or aweight of the OHV, a power capacity associated with the primary electricpower generator, an efficiency rating of a component of the OHV, apresent speed of the OHV, an anticipated speed of the OHV, a presentelectrical load of the OHV, and an anticipated electrical load of theOHV; and dissipating instructions for controlling during braking thetravel of the OHV the operation of each of the plurality of gridswitching devices in the dynamic braking resistance grid circuits tocontrol the flow of electrical power from the DC bus to the respectiveresistance grid, wherein the dissipating instructions control a dutycycle of at least one of the plurality of grid switching devices suchelectrical power generated by the vehicle propulsion system that theelectrical energy capture system is able to store is not dissipate bythe plurality of resistive grids.
 14. The computer executableinstructions of claim 13, wherein the transmission instructions controlthe transmission of power to and from a traction motor, said tractionmotor connected to a vehicle wheel and operable as a motor in themotoring mode of the vehicle propulsion system and as a generator in thedynamic braking mode of the vehicle propulsion system, wherein thetransmission instructions maximize the storage of excess electricalpower from the DC bus in the energy capture system during braking. 15.The computer executable instructions of claim 13, wherein thetransmission instructions control the transmission of electrical powerto and from a plurality of traction motors, wherein a pair of vehiclewheels is associated with each traction motor.
 16. The computerexecutable instructions of claim 13, wherein the transmissioninstructions control the operation of a power switching device in acircuit with the primary electric power generator, the vehiclepropulsion system, an electrical energy capture system, and each of theplurality of dynamic braking resistance grid circuits to control thetransmission of electrical power among the primary electric powergenerator, the vehicle propulsion system, an electrical energy capturesystem, and each of the plurality of dynamic braking resistance gridcircuits.
 17. The computer executable instructions of claim 13, whereinthe OHV further comprises electrical connections for connecting the DCbus to an external source of electrical power, and wherein the whereinthe transmission instructions control the electrical connections toselectively connect the DC bus to an external source of electrical powerto control the transmission of electrical power from the external sourceof electrical power to the DC bus.
 18. The computer executableinstructions of claim 13, wherein the transmission instructions controlthe operation of an energy storage switching device in a circuit withthe DC bus and the electrical energy capture system to control the flowof electrical power to and from the electrical energy capture system,wherein the energy storage switching device comprises a contactor switchor chopper circuit.
 19. The computer executable instructions of claim18, wherein transmission instructions control the operation of theenergy storage switching device to control the transmission ofelectrical power to an electric storage battery.
 20. The computerexecutable instructions of claim 18, wherein transmission instructionscontrol the operation of the energy storage switching device to controlthe transmission of electrical power to a storage device selected fromthe group comprising ultra-capacitors, flywheel-generators, and fuelcells.
 21. The computer executable instructions of claim 13, wherein theOHV further includes an auxiliary electric power generator forgenerating auxiliary electrical power and electrically connected to theelectrical energy capture system, and wherein the transmissioninstructions control the transmission of power from the auxiliaryelectric power generator.
 22. The computer executable instructions ofclaim 21, wherein the OHV further comprises auxiliary electric powerloads electrically connected to the auxiliary power generator, andwherein the transmission instructions control the transmission of powerto the auxiliary electric power generator.
 23. The computer executableinstructions of claim 13, wherein the processor is operatively connectedto a computer readable medium storing track topography data and a OHVlocator locating a current position of the OHV, wherein the computerexecutable instructions further include determining instructions fordetermining future OHV electric energy requirements as a function of thetrack topography data and the current position of the OHV, saidtransmission instructions responsive to the determined future energyrequirements to control the flow of electrical power among the primaryelectric power generator, the vehicle propulsion system, the electricalenergy capture system, and each of the plurality of dynamic resistancebraking grid circuits as a function of the determined future OHVelectric energy requirements.
 24. The computer executable instructionsof claim 13, wherein at least one of the grid switching devicescomprises an electronic power management chopper switch, and wherein thedissipating instructions control the operation of the electronic powermanagement chopper switch to control the flow of electrical power to therespective resistance grid.
 25. A method for operating a hybrid energy,electro-motive, self-powered off-highway vehicle (OHV) including aplurality of wheels for supporting and propelling the OHV, a vehiclepropulsion system mechanically coupled to at least one of the wheels ofthe OHV; a primary electric power generator carried on the OHV forgenerating primary electrical power to be supplied to the vehiclepropulsion system, said vehicle propulsion system having a motoring modein which the propulsion system is responsive to electric power suppliedto the propulsion system for generating mechanical energy that isapplied to said wheel for propelling the vehicle, and said vehiclepropulsion system further having a dynamic braking mode in which thepropulsion system is response to mechanical energy from said wheelduring dynamic braking operations of the OHV for generating dynamicbraking electrical power; an electrical energy capture system carried onthe vehicle for storing electrical power generated on the OHV and fordischarging the stored electrical power for use on the OHV, includingselectively using the stored electric power to propel the OHV; a directcurrent (DC) bus for electrically connecting the primary electric powergenerator, vehicle propulsion system and electrical energy capturesystem; a plurality of dynamic braking resistance grid circuitselectrically connected to the vehicle propulsion system for dissipatingexcess electrical power on the OHV, with each grid circuit including atleast one dynamic braking resistance grid and being connected to the DCbus; a plurality of grid switching devices in the dynamic braking gridcircuits, with at least one grid switching device for each dynamicbraking grid circuit for controlling the flow of electrical power to therespective resistance grid, said method comprising: controlling thetransmission of electrical power among the primary electric powergenerator, the vehicle propulsion system, an electrical energy capturesystem, and each of the plurality of dynamic braking resistance gridcircuits as a function of transmission instructions during motoring,operating and braking the travel of the OHV said controlling comprising:providing a first control signal from an energy management processor ofthe OHV to the electrical energy capture system to control the selectivestoring of electrical energy generated in the dynamic braking mode as afunction of said transmission instructions and to control the selectiveproviding of secondary electric power to the vehicle propulsion systemas a function of at least one of the following: a travel path situationparameter, a manual operator input, a size or a weight of the OHV, apower capacity associated with the primary electric power generator, anefficiency rating of a component of the OHV, a present speed of the OHV,an anticipated speed of the OHV, a present electrical load of the OHV,and an anticipated electrical load of the OHV, and providing a secondcontrol signal from the processor of the OHV to the primary electricpower generator to control the selective supplying of primary electricpower to the vehicle propulsion system as a function of at least one ofthe following: a travel path situation parameter, a manual operatorinput, a size or a weight of the OHV, a power capacity associated withthe primary electric power generator, an efficiency rating of acomponent of the OHV, a present speed of the OHV, an anticipated speedof the OHV, a present electrical load of the OHV, and an anticipatedelectrical load of the OHV; and controlling the transmission ofelectrical power during braking of the travel of the OHV to each of thedynamic braking resistance grid circuits as a function of dissipatinginstructions for controlling the amount of excess electrical powerdissipated in the respective resistance grid, wherein the dissipatinginstructions control a duty cycle of at least one of the plurality ofgrid switching devices such that electrical power generated by thevehicle propulsion system that the electrical energy capture system isable to store is not dissipated by the plurality of resistive grids. 26.The method of claim 25, wherein controlling the transmission ofelectrical power includes controlling power to and from a tractionmotor, said traction motor connected to a vehicle wheel and operable asa motor in the motoring mode of the vehicle propulsion system and as agenerator in the dynamic braking mode of the vehicle propulsion system,and wherein the transmission instructions maximize the storage of excesselectrical power from the DC bus in the energy capture system duringbraking.
 27. The method of claim 26, wherein controlling thetransmission of electrical power includes controlling power to and froma plurality of traction motors, wherein a pair of vehicle wheels isassociated with each traction motor.
 28. The method of claim 27, whereincontrolling the transmission of electrical power includes controllingthe operation of a power switching device in a circuit with at least oneof the traction motors to control the transmission of power to and fromthe traction motor.
 29. The method of claim 25, further includingselectively connecting the DC bus to an external source of electricalpower, and wherein controlling the transmission of electrical powerincludes controlling transmission of power from the external source ofelectrical power to the DC bus.
 30. The method of claim 25, whereincontrolling the transmission of electrical power includes thecontrolling the operation of an energy storage switching device in acircuit with the DC bus and the electrical energy capture system tocontrol the flow of electrical power to and from the electrical energycapture system, wherein the energy storage switching device comprises acontactor switch.
 31. The method of claim 30, wherein controllingtransmission of electrical power includes controlling the transmissionof power to an electric storage battery.
 32. The method of claim 30,wherein controlling transmission of electrical power includescontrolling the transmission of power to a storage device selected fromthe group comprising ultra-capacitors, flywheel-generators, and fuelcells.
 33. The method of claim 25, wherein the OHV further includes anauxiliary electric power generator for generating auxiliary electricalpower and electrically connected to the electrical energy capturesystem, and wherein controlling transmission of electrical powerincludes controlling the transmission of power from the auxiliaryelectric power generator.
 34. The method of claim 33, wherein the OHVfurther comprises auxiliary electric power loads electrically connectedto the auxiliary power generator, and wherein controlling transmissionof electrical power includes controlling the transmission of power tothe auxiliary electric power generator.
 35. The method of claim 25,further including: storing track topography data in a memory; receivinga current position of the OHV from a position identification system; andpredicting future OHV electric energy requirements as a function of thetrack topography data and the received current position of the OHV. 36.The method of claim 25, wherein the OHV is a mining truck or a railroadtrain.